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Raphael KL. Metabolic Acidosis in CKD: Pathogenesis, Adverse Effects, and Treatment Effects. Int J Mol Sci 2024; 25:5187. [PMID: 38791238 PMCID: PMC11121226 DOI: 10.3390/ijms25105187] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2023] [Revised: 04/28/2024] [Accepted: 05/05/2024] [Indexed: 05/26/2024] Open
Abstract
Metabolic acidosis is a frequent complication of chronic kidney disease and is associated with a number of adverse outcomes, including worsening kidney function, poor musculoskeletal health, cardiovascular events, and death. Mechanisms that prevent metabolic acidosis detrimentally promote further kidney damage, creating a cycle between acid accumulation and acid-mediated kidney injury. Disrupting this cycle through the provision of alkali, most commonly using sodium bicarbonate, is hypothesized to preserve kidney function while also mitigating adverse effects of excess acid on bone and muscle. However, results from clinical trials have been conflicting. There is also significant interest to determine whether sodium bicarbonate might improve patient outcomes for those who do not have overt metabolic acidosis. Such individuals are hypothesized to be experiencing acid-mediated organ damage despite having a normal serum bicarbonate concentration, a state often referred to as subclinical metabolic acidosis. Results from small- to medium-sized trials in individuals with subclinical metabolic acidosis have also been inconclusive. Well-powered clinical trials to determine the efficacy and safety of sodium bicarbonate are necessary to determine if this intervention improves patient outcomes.
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Affiliation(s)
- Kalani L. Raphael
- Division of Nephrology & Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, UT 84112, USA;
- Medicine Section, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, UT 84148, USA
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Sorohan BM, Obrișcă B, Jurubiță R, Lupușoru G, Achim C, Andronesi A, Frățilă G, Berechet A, Micu G, Ismail G. Sodium citrate versus sodium bicarbonate for metabolic acidosis in patients with chronic kidney disease: A randomized controlled trial. Medicine (Baltimore) 2024; 103:e37475. [PMID: 38457574 PMCID: PMC10919529 DOI: 10.1097/md.0000000000037475] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2024] [Revised: 01/29/2024] [Accepted: 02/12/2024] [Indexed: 03/10/2024] Open
Abstract
BACKGROUND Metabolic acidosis (MA) is frequently associated with chronic kidney disease (CKD) progression. Our aim was to compare the effect of oral sodium citrate (SC) with that of oral sodium bicarbonate (SB) on renal function and serum bicarbonate correction, as well as to evaluate their safety profile in patients with MA of CKD. METHODS We conducted a prospective, single-center, randomized 1:1, parallel, controlled, unblinded clinical trial of 124 patients with MA and CKD stages 3b and 4. The primary outcome was the mean change in estimated glomerular filtration rate (eGFR). The secondary outcomes were mean change in serum bicarbonate level, eGFR decrease by 30%, eGFR decrease by 50%, dialysis, death or prolonged hospitalization, and a combined endpoint. RESULTS No significant difference was found between the groups in terms of mean eGFR change [adjusted mean difference = -0.99 mL/min/1.73 m2 (95% CI: -2.51 to 0.93, P = .20)]. We observed a mean serum bicarbonate change of 6.15 mmol/L [(95% CI: 5.55-6.74), P < .001] in the SC group and of 6.19 mmol/L [(95% CI: 5.54-6.83), P < .001] in the SB group, but no significant difference between the 2 groups [adjusted mean difference = 0.31 mmol/L (-0.22 to 0.85), P = .25]. Cox proportional hazard analysis showed similar risks regarding eGFR decrease by 30% (P = .77), eGFR decrease by 50% (P = .50), dialysis (P = .85), death or prolonged hospitalization (P = .29), and combined endpoint (P = .57). Study drug discontinuation due to adverse events was significantly more common in the SB group (17.7% vs 4.8%, P = .02). CONCLUSIONS SC and SB have a similar effect on kidney function decline, both improve serum bicarbonate level, but SB is associated with higher rates of medication discontinuation due to adverse events.
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Affiliation(s)
- Bogdan Marian Sorohan
- “Carol Davila” University of Medicine and Pharmacy, Department of Nephrology, Bucharest, Romania
- Fundeni Clinical Institute, Department of Kidney Transplantation, Bucharest, Romania
| | - Bogdan Obrișcă
- “Carol Davila” University of Medicine and Pharmacy, Department of Nephrology, Bucharest, Romania
- Fundeni Clinical Institute, Department of Nephrology, Bucharest, Romania
| | - Roxana Jurubiță
- “Carol Davila” University of Medicine and Pharmacy, Department of Nephrology, Bucharest, Romania
- Fundeni Clinical Institute, Department of Nephrology, Bucharest, Romania
| | - Gabriela Lupușoru
- “Carol Davila” University of Medicine and Pharmacy, Department of Nephrology, Bucharest, Romania
- Fundeni Clinical Institute, Department of Nephrology, Bucharest, Romania
| | - Camelia Achim
- “Carol Davila” University of Medicine and Pharmacy, Department of Nephrology, Bucharest, Romania
- Fundeni Clinical Institute, Department of Nephrology, Bucharest, Romania
| | - Andreea Andronesi
- “Carol Davila” University of Medicine and Pharmacy, Department of Nephrology, Bucharest, Romania
- Fundeni Clinical Institute, Department of Nephrology, Bucharest, Romania
| | - Georgiana Frățilă
- “Carol Davila” University of Medicine and Pharmacy, Department of Nephrology, Bucharest, Romania
| | - Andreea Berechet
- Fundeni Clinical Institute, Department of Nephrology, Bucharest, Romania
| | - Georgia Micu
- Fundeni Clinical Institute, Department of Nephrology, Bucharest, Romania
| | - Gener Ismail
- “Carol Davila” University of Medicine and Pharmacy, Department of Nephrology, Bucharest, Romania
- Fundeni Clinical Institute, Department of Nephrology, Bucharest, Romania
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Goraya N, Wesson DE. Pathophysiology of Diet-Induced Acid Stress. Int J Mol Sci 2024; 25:2336. [PMID: 38397012 PMCID: PMC10888592 DOI: 10.3390/ijms25042336] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 02/13/2024] [Accepted: 02/14/2024] [Indexed: 02/25/2024] Open
Abstract
Diets can influence the body's acid-base status because specific food components yield acids, bases, or neither when metabolized. Animal-sourced foods yield acids and plant-sourced food, particularly fruits and vegetables, generally yield bases when metabolized. Modern diets proportionately contain more animal-sourced than plant-sourced foods, are, thereby, generally net acid-producing, and so constitute an ongoing acid challenge. Acid accumulation severe enough to reduce serum bicarbonate concentration, i.e., manifesting as chronic metabolic acidosis, the most extreme end of the continuum of "acid stress", harms bones and muscles and appears to enhance the progression of chronic kidney disease (CKD). Progressive acid accumulation that does not achieve the threshold amount necessary to cause chronic metabolic acidosis also appears to have deleterious effects. Specifically, identifiable acid retention without reduced serum bicarbonate concentration, which, in this review, we will call "covert acidosis", appears to cause kidney injury and exacerbate CKD progression. Furthermore, the chronic engagement of mechanisms to mitigate the ongoing acid challenge of modern diets also appears to threaten health, including kidney health. This review describes the full continuum of "acid stress" to which modern diets contribute and the mechanisms by which acid stress challenges health. Ongoing research will develop clinically useful tools to identify stages of acid stress earlier than metabolic acidosis and determine if dietary acid reduction lowers or eliminates the threats to health that these diets appear to cause.
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Affiliation(s)
- Nimrit Goraya
- Department of Internal Medicine, Baylor Scott & White Health, Temple, TX 76508, USA;
- Department of Internal Medicine, Texas A&M Health Science Center College of Medicine, Temple, TX 76508, USA
| | - Donald E. Wesson
- Department of Internal Medicine, Dell Medical School, The University of Texas at Austin, Dallas, TX 78712, USA
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Wang YC, Ling XC, Tsai WH, Liu JS, Kuo KL. Risks of Topical Carbonic Anhydrase Inhibitors in Glaucoma Patients With Chronic Kidney Disease: A Nationwide Population-Based Study. Am J Ophthalmol 2023; 253:49-55. [PMID: 37149244 DOI: 10.1016/j.ajo.2023.05.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2022] [Revised: 04/27/2023] [Accepted: 05/01/2023] [Indexed: 05/08/2023]
Abstract
PURPOSE To investigate the risks of metabolic acidosis and renal outcomes after topical carbonic anhydrase inhibitor (CAI) use in patients with both primary open-angle glaucoma (POAG) and advanced chronic kidney disease (CKD). DESIGN Nationwide, population-based cohort study. METHODS This study was conducted with population data from Taiwan's National Health Insurance (NHI) Research Database between January 2000 and June 2009. Patients with advanced CKD who were diagnosed with glaucoma (International Classification of Diseases, Ninth Revision [ICD-9] code 365) and had been receiving eye drops for glaucoma (including carbonic anhydrase inhibitors selected by NHI drug code) were enrolled. Using Kaplan-Meier methods, we compared the cumulative incidence of mortality, long-term dialysis, and cumulative incidence of metabolic acidosis over time between CAI users and CAI non-users. Primary outcomes comprised mortality, renal outcome (progression to hemodialysis), and metabolic acidosis. RESULTS In this cohort, topical CAI users had a higher incidence of long-term dialysis than non-users (incidence = 1,216.85 vs 764.17 events per 100 patient-years; adjusted hazard ratio = 1.17, 95% CI = 1.01-1.37). Hospital admissions due to metabolic acidosis were higher in CAI users compared with non-users (incidence = 21.54 vs 11.87 events per 100 patient-years; adjusted hazard ratio = 1.89, 95% CI = 1.07-3.36). CONCLUSIONS Topical CAIs may be associated with higher risks of long-term dialysis and metabolic acidosis in patients with POAG and pre-dialysis advanced CKD. Therefore, topical CAIs should be used with caution in advanced CKD patients.
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Affiliation(s)
- Yi-Chun Wang
- From the Division of Nephrology (Y.-C.W., K.-L.K.), Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei, Taiwan; School of Medicine (Y.-C.W., W.-H.T., K.-L.K.), Buddhist Tzu Chi University, Hualien, Taiwan
| | - Xiao Chun Ling
- Department of Ophthalmology (X.C.L.), Chang Gung Memorial Hospital, Linkou, Taoyuan, Taiwan
| | - Wen-Hsin Tsai
- School of Medicine (Y.-C.W., W.-H.T., K.-L.K.), Buddhist Tzu Chi University, Hualien, Taiwan; Department of Pediatrics (W.-H.T.), Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation
| | - Jia-Sin Liu
- Department of Public Health (J.-S.L.), Kaohsiung Medical University, Kaohsiung, Taiwan
| | - Ko-Lin Kuo
- From the Division of Nephrology (Y.-C.W., K.-L.K.), Taipei Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, New Taipei, Taiwan; School of Medicine (Y.-C.W., W.-H.T., K.-L.K.), Buddhist Tzu Chi University, Hualien, Taiwan; School of Post-Baccalaureate Chinese Medicine (K.-L.K.), Tzu Chi University, Hualien, Taiwan.
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Cheng YL, Huang SC, Ho MY, Li YR, Yen CL, Chen KH, Sun WC, Fan PY, Chen JS, Lin C, Hsiao CC. Effect of sodium bicarbonate on cardiovascular outcome and mortality in patients with advanced chronic kidney disease. Front Pharmacol 2023; 14:1146668. [PMID: 37251318 PMCID: PMC10213883 DOI: 10.3389/fphar.2023.1146668] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2023] [Accepted: 04/20/2023] [Indexed: 05/31/2023] Open
Abstract
Background: Metabolic acidosis is a common complication in patients with chronic kidney disease (CKD). Oral sodium bicarbonate is often used to treat metabolic acidosis and prevent CKD progression. However, there is limited information about the effect of sodium bicarbonate on major adverse cardiovascular events (MACE) and mortality in patients with pre-dialysis advanced CKD. Method: 25599 patients with CKD stage V between January 1, 2001 and December 31, 2019 were identified from the Chang Gung Research Database (CGRD), a multi-institutional electronic medical record database in Taiwan. The exposure was defined as receiving sodium bicarbonate or not. Baseline characteristics were balanced using propensity score weighting between two groups. Primary outcomes were dialysis initiation, all-cause mortality, and major adverse cardiovascular events (MACE) (myocardial infarction, heart failure, stroke). The risks of dialysis, MACE, and mortality were compared between two groups using Cox proportional hazards models. In addition, we performed analyzes using Fine and Gray sub-distribution hazard models that considered death as a competing risk. Result: Among 25599 patients with CKD stage V, 5084 patients (19.9%) were sodium bicarbonate users while 20515 (80.1%) were sodium bicarbonate non-users. The groups had similar risk of dialysis initiation (hazard ratio (HR): 0.98, 95% confidence interval (CI): 0.95-1.02, p < 0.379). However, taking sodium bicarbonate was associated with a significantly lower risks of MACE (HR: 0.95, 95% CI 0.92-0.98, p < 0.001) and hospitalizations for acute pulmonary edema (HR: 0.92, 95% CI 0.88-0.96, p < 0.001) compared with non-users. The mortality risks were significantly lower in sodium bicarbonate users compared with sodium bicarbonate non-users (HR: 0.75, 95% CI 0.74-0.77, p < 0.001). Conclusion: This cohort study revealed that in real world practice, use of sodium bicarbonate was associated with similar risk of dialysis compared with non-users among patients with advanced CKD stage V. Nonetheless, use of sodium bicarbonate was associated with significantly lower rate of MACE and mortality. Findings reinforce the benefits of sodium bicarbonate therapy in the expanding CKD population. Further prospective studies are needed to confirm these findings.
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Affiliation(s)
- Ya-Lien Cheng
- Kidney Research Center and Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Shu-Chun Huang
- Department of Physical Medicine and Rehabilitation, New Taipei Municipal Tucheng Hospital, Chang Gung Memorial Hospital, New Taipei, Taiwan
| | - Ming-Yun Ho
- Division of Cardiology, Department of Internal Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Yan-Rong Li
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
| | - Chieh-Li Yen
- Kidney Research Center and Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Kuan-Hsing Chen
- Kidney Research Center and Department of Nephrology, Linkou Chang Gung Memorial Hospital, Taoyuan, Taiwan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
| | - Wei-Chiao Sun
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Nephrology, New Taipei Municipal Tucheng Hospital, New Taipei, Taiwan
| | - Pei-Yi Fan
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Nephrology, New Taipei Municipal Tucheng Hospital, New Taipei, Taiwan
| | - Jung-Sheng Chen
- Center for Artificial Intelligence in Medicine, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Chihung Lin
- Center for Artificial Intelligence in Medicine, Chang Gung Memorial Hospital at Linkou, Taoyuan, Taiwan
| | - Ching-Chung Hsiao
- College of Medicine, Chang Gung University, Taoyuan, Taiwan
- Department of Nephrology, New Taipei Municipal Tucheng Hospital, New Taipei, Taiwan
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Phetsanthad A, Vu NQ, Yu Q, Buchberger AR, Chen Z, Keller C, Li L. Recent advances in mass spectrometry analysis of neuropeptides. MASS SPECTROMETRY REVIEWS 2023; 42:706-750. [PMID: 34558119 PMCID: PMC9067165 DOI: 10.1002/mas.21734] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 08/22/2021] [Accepted: 08/28/2021] [Indexed: 05/08/2023]
Abstract
Due to their involvement in numerous biochemical pathways, neuropeptides have been the focus of many recent research studies. Unfortunately, classic analytical methods, such as western blots and enzyme-linked immunosorbent assays, are extremely limited in terms of global investigations, leading researchers to search for more advanced techniques capable of probing the entire neuropeptidome of an organism. With recent technological advances, mass spectrometry (MS) has provided methodology to gain global knowledge of a neuropeptidome on a spatial, temporal, and quantitative level. This review will cover key considerations for the analysis of neuropeptides by MS, including sample preparation strategies, instrumental advances for identification, structural characterization, and imaging; insightful functional studies; and newly developed absolute and relative quantitation strategies. While many discoveries have been made with MS, the methodology is still in its infancy. Many of the current challenges and areas that need development will also be highlighted in this review.
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Affiliation(s)
- Ashley Phetsanthad
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Nhu Q. Vu
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Qing Yu
- School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, WI 53705, USA
| | - Amanda R. Buchberger
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Zhengwei Chen
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Caitlin Keller
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
| | - Lingjun Li
- Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, WI 53706, USA
- School of Pharmacy, University of Wisconsin-Madison, 777 Highland Avenue, Madison, WI 53705, USA
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Paradigm shift in lifestyle modification for solitary kidney after donor nephrectomy. Curr Opin Nephrol Hypertens 2023; 32:67-75. [PMID: 36444664 DOI: 10.1097/mnh.0000000000000853] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
PURPOSE OF REVIEW Living donor kidney transplantation potentially leads to long-term complications including chronic kidney disease, end-stage kidney disease, elevated blood pressure, and pregnancy-associated hypertension. Given living donors generally do not have underlying medical conditions, lifestyle modifications, particularly dietary interventions may prevent those complications and improve their health outcomes. RECENT FINDINGS Glomerular hyperfiltration occurs as physiologic adaptation during an initial postdonor nephrectomy period. In the long-term, these adaptations may become pathologic consequences resulting from hyperfiltration-mediated kidney injury and ultimately secondary focal segmental glomerulosclerosis in the solitary kidney. Dietary interventions to slow a decline in kidney function include low protein intake of <0.8 g/kg/day and low sodium consumption of 2-4 g/day as well as certain health dietary patterns. There is no evidence regarding the quantity and quality of protein that can be recommended for living kidney donors and the same for sodium. Plant Dominant (PLADO) diets, Dietary Approaches to Stop Hypertension (DASH), Mediterranean, and vegetarian diets may be favorable for living kidney donors with solitary kidney but the evidence is still lacking. SUMMARY Although dietary interventions may provide benefits and kidney health for living kidney donors, further studies including clinical trials are required to incorporate them into clinical practice guidelines.
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Tariq H, Dobre M. Metabolic acidosis post kidney transplantation. Front Physiol 2022; 13:989816. [PMID: 36082221 PMCID: PMC9445136 DOI: 10.3389/fphys.2022.989816] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 08/01/2022] [Indexed: 11/23/2022] Open
Abstract
Metabolic acidosis, a common complication in patients with chronic kidney disease (CKD), results in a multitude of deleterious effects. Though the restoration of kidney function following transplantation is generally accompanied by a correction of metabolic acidosis, a subset of transplant recipients remains afflicted by this ailment and its subsequent morbidities. The vulnerability of kidney allografts to metabolic acidosis can be attributed to reasons similar to pathogenesis of acidosis in non-transplant CKD, and to transplant specific causes, including donor related, recipient related, immune mediated factors, and immunosuppressive medications. Correction of metabolic acidosis in kidney transplantation either with alkali therapy or through dietary manipulations may have potential benefits and the results of such clinical trials are eagerly awaited. This review summarizes the published evidence on the pathogenesis and clinical consequences of chronic metabolic acidosis in kidney transplant recipients.
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Affiliation(s)
- Hafsa Tariq
- Division of Nephrology, University of Rochester Medical Center, Rochester, NY, United States
| | - Mirela Dobre
- Division of Nephrology and Hypertension, University Hospitals Cleveland Medical Center, Case Western Reserve University, Cleveland, OH, United States
- *Correspondence: Mirela Dobre,
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Zhu A, Whitlock RH, Ferguson TW, Nour-Mohammadi M, Komenda P, Rigatto C, Collister D, Bohm C, Reaven NL, Funk SE, Tangri N. Metabolic Acidosis is Associated With Acute Kidney Injury in Patients With CKD. Kidney Int Rep 2022; 7:2219-2229. [PMID: 36217527 PMCID: PMC9546743 DOI: 10.1016/j.ekir.2022.07.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 06/27/2022] [Accepted: 07/05/2022] [Indexed: 12/13/2022] Open
Abstract
Introduction Metabolic acidosis in patients with chronic kidney disease (CKD) results from a loss of kidney function. It has been associated with CKD progression, all-cause mortality, and other adverse outcomes. We aimed to determine whether metabolic acidosis is associated with a higher risk of acute kidney injury (AKI). Methods This was a retrospective cohort study. Using electronic health records and administrative data, we enrolled 2 North American cohorts of patients with CKD Stages G3-G5 as follows: (i) 136,067 patients in the US electronic medical record (EMR) based cohort; and (ii) 34,957 patients in the Manitoba claims-based cohort. The primary exposure was metabolic acidosis (serum bicarbonate between 12 mEq/l and <22 mEq/l). The primary outcome was the development of AKI (defined using ICD-9 and 10 codes at hospital admission or a laboratory-based definition based on Kidney Disease: Improving Global Outcomes guidelines). We applied Cox proportional hazards regression models adjusting for relevant demographic and clinical characteristics. Results In both cohorts, metabolic acidosis was associated with AKI: hazard ratio (HR) 1.57 (95% confidence interval [CI] 1.52-1.61) in the US EMR cohort, and HR 1.65 (95% CI 1.58-1.73) in the Manitoba claims cohort. The association was consistent when serum bicarbonate was treated as a continuous variable, and in multiple subgroups, and sensitivity analyses including those adjusting for albuminuria. Conclusion Metabolic acidosis is associated with a higher risk of AKI in patients with CKD. AKI should be considered as an outcome in studies of treatments for patients with metabolic acidosis.
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Affiliation(s)
- Antonia Zhu
- Department of Internal Medicine, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Reid H. Whitlock
- Seven Oaks General Hospital, Chronic Disease Innovation Center, Winnipeg, Manitoba, Canada
| | - Thomas W. Ferguson
- Department of Internal Medicine, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
- Seven Oaks General Hospital, Chronic Disease Innovation Center, Winnipeg, Manitoba, Canada
| | | | - Paul Komenda
- Department of Internal Medicine, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
- Seven Oaks General Hospital, Chronic Disease Innovation Center, Winnipeg, Manitoba, Canada
| | - Claudio Rigatto
- Department of Internal Medicine, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
- Seven Oaks General Hospital, Chronic Disease Innovation Center, Winnipeg, Manitoba, Canada
| | - David Collister
- Department of Internal Medicine, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
- Seven Oaks General Hospital, Chronic Disease Innovation Center, Winnipeg, Manitoba, Canada
| | - Clara Bohm
- Department of Internal Medicine, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
- Seven Oaks General Hospital, Chronic Disease Innovation Center, Winnipeg, Manitoba, Canada
| | - Nancy L. Reaven
- Strategic Health Resources, La Cañada Flintridge, California, USA
| | - Susan E. Funk
- Strategic Health Resources, La Cañada Flintridge, California, USA
| | - Navdeep Tangri
- Department of Internal Medicine, Max Rady College of Medicine, University of Manitoba, Winnipeg, Manitoba, Canada
- Seven Oaks General Hospital, Chronic Disease Innovation Center, Winnipeg, Manitoba, Canada
- Correspondence: Navdeep Tangri, Seven Oaks General Hospital, 2300 McPhillips Street, 2LB19 Winnipeg, Manitoba R2V 3M3, Canada.
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Wesson DE. The Importance of Recognizing and Addressing the Spectrum of Acid Stress. Adv Chronic Kidney Dis 2022; 29:364-372. [PMID: 36175074 DOI: 10.1053/j.ackd.2022.06.001] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2022] [Revised: 06/01/2022] [Accepted: 06/09/2022] [Indexed: 01/25/2023]
Abstract
Acid accumulation sufficient to reduce plasma bicarbonate concentration, thereby recognized as chronic metabolic acidosis, harms bones and muscles and appears to enhance progression of CKD. Evolving evidence supports that progressive acid accumulation that is not enough to cause chronic metabolic acidosis nevertheless has deleterious effects. Measurable acid retention without reduced plasma bicarbonate concentration, called eubicarbonatemic acidosis, also appears to cause kidney injury and exacerbate CKD progression. Furthermore, chronic engagement of mechanisms to mitigate the ongoing acid challenge of net acid-producing diets of developed societies also appears to be deleterious, including for kidney health. This review challenges clinicians to consider the growing evidence for a spectrum of acid-accumulation disorders that include lesser degrees of acid accumulation than metabolic acidosis yet are harmful. Further research will develop clinically useful tools to identify individuals suffering from these earlier stages of acid stress and determine if the straightforward and comparatively inexpensive intervention of dietary acid reduction relieves or eliminates the harm they appear to cause.
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Affiliation(s)
- Donald E Wesson
- The University of Texas at Austin Dell Medical School, Austin, TX; Donald E Wesson Consulting LLC, Dallas, TX.
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11
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Goraya N, Narayanan M, Wesson DE. Management of Metabolic Acidosis in Chronic Kidney Disease: Past, Present, and Future Direction. Adv Chronic Kidney Dis 2022; 29:416-423. [PMID: 36175079 DOI: 10.1053/j.ackd.2022.02.011] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 02/20/2022] [Accepted: 02/28/2022] [Indexed: 01/25/2023]
Abstract
Chronic kidney disease (CKD) is a major global epidemic associated with increased morbidity and mortality. Despite the effectiveness of kidney protection strategies of hypertension, diabetes, and lipid control and use of newer hypoglycemic agents and anti-angiotensin II drugs, the nephropathy in CKD continues unabated toward irreversible kidney failure. Thus, interventions targeting modifiable risk factors in CKD such as metabolic acidosis (MA) are needed. Acid reduction with sodium-based alkali has been shown to be an effective kidney-protection strategy for patients with CKD and reduced glomerular filtration rate (GFR). Small-scale studies reveal diets emphasizing ingestion of plant-sourced over animal-sourced protein reduce dietary acid, improve MA, and slow further nephropathy progression in patients with CKD and reduced GFR. Additionally, veverimer, an investigational, nonabsorbed polymer that binds and removes gastrointestinal hydrochloric acid, is being developed as a novel treatment for MA. As further studies define how to best use these interventions for kidney protection, clinicians must become aware of their potential utility in the management of patients with CKD. The aim of the present review is to explore the various intervention strategies that increase or normalize serum [HCO3-] in patients with CKD-associated MA or low normal serum [HCO3-] that may further slow progression of CKD.
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Affiliation(s)
- Nimrit Goraya
- Scott & White Medical Center-Temple, Division of Nephrology and Hypertension, Department of Medicine, Temple, TX.
| | - Mohanram Narayanan
- Scott & White Medical Center-Temple, Division of Nephrology and Hypertension, Department of Medicine, Temple, TX
| | - Donald E Wesson
- Dell Medical School, The University of Texas at Austin, Austin, TX
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Ravikumar NPG, Pao AC, Raphael KL. Acid-Mediated Kidney Injury Across the Spectrum of Metabolic Acidosis. Adv Chronic Kidney Dis 2022; 29:406-415. [PMID: 36175078 DOI: 10.1053/j.ackd.2022.04.009] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2022] [Revised: 04/15/2022] [Accepted: 04/25/2022] [Indexed: 01/25/2023]
Abstract
Metabolic acidosis affects about 15% of patients with chronic kidney disease. As kidney function declines, the kidneys progressively fail to eliminate acid, primarily reflected by a decrease in ammonium and titratable acid excretion. Several studies have shown that the net acid load remains unchanged in patients with reduced kidney function; the ensuing acid accumulation can precede overt metabolic acidosis, and thus, indicators of urinary acid or potential base excretion, such as ammonium and citrate, may serve as early signals of impending metabolic acidosis. Acid retention, with or without overt metabolic acidosis, initiates compensatory responses that can promote tubulointerstitial fibrosis via intrarenal complement activation and upregulation of endothelin-1, angiotensin II, and aldosterone pathways. The net effect is a cycle between acid accumulation and kidney injury. Results from small- to medium-sized interventional trials suggest that interrupting this cycle through base administration can prevent further kidney injury. While these findings inform current clinical practice guidelines, large-scale clinical trials are still necessary to prove that base therapy can limit chronic kidney disease progression or associated adverse events.
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Affiliation(s)
- Naveen P G Ravikumar
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, OR; Veterans Affairs Portland Health Care System, Portland, OR
| | - Alan C Pao
- Division of Nephrology, Department of Medicine, Stanford University School of Medicine, Stanford, CA; Veterans Affairs Palo Alto Health Care System, Palo Alto, CA
| | - Kalani L Raphael
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University, Portland, OR; Veterans Affairs Portland Health Care System, Portland, OR.
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13
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Imenez Silva PH, Mohebbi N. Kidney metabolism and acid-base control: back to the basics. Pflugers Arch 2022; 474:919-934. [PMID: 35513635 PMCID: PMC9338915 DOI: 10.1007/s00424-022-02696-6] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 04/27/2022] [Accepted: 04/28/2022] [Indexed: 01/18/2023]
Abstract
Kidneys are central in the regulation of multiple physiological functions, such as removal of metabolic wastes and toxins, maintenance of electrolyte and fluid balance, and control of pH homeostasis. In addition, kidneys participate in systemic gluconeogenesis and in the production or activation of hormones. Acid-base conditions influence all these functions concomitantly. Healthy kidneys properly coordinate a series of physiological responses in the face of acute and chronic acid-base disorders. However, injured kidneys have a reduced capacity to adapt to such challenges. Chronic kidney disease patients are an example of individuals typically exposed to chronic and progressive metabolic acidosis. Their organisms undergo a series of alterations that brake large detrimental changes in the homeostasis of several parameters, but these alterations may also operate as further drivers of kidney damage. Acid-base disorders lead not only to changes in mechanisms involved in acid-base balance maintenance, but they also affect multiple other mechanisms tightly wired to it. In this review article, we explore the basic renal activities involved in the maintenance of acid-base balance and show how they are interconnected to cell energy metabolism and other important intracellular activities. These intertwined relationships have been investigated for more than a century, but a modern conceptual organization of these events is lacking. We propose that pH homeostasis indissociably interacts with central pathways that drive progression of chronic kidney disease, such as inflammation and metabolism, independent of etiology.
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Affiliation(s)
- Pedro Henrique Imenez Silva
- Institute of Physiology, University of Zurich, Winterthurerstrasse 190, CH-8057, Zurich, Switzerland.
- National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland.
| | - Nilufar Mohebbi
- National Center of Competence in Research NCCR Kidney.CH, Zurich, Switzerland
- Praxis Und Dialysezentrum Zurich, Zurich, Switzerland
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14
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Fukasawa H, Kaneko M, Uchiyama Y, Yasuda H, Furuya R. Lower bicarbonate level is associated with CKD progression and all-cause mortality: a propensity score matching analysis. BMC Nephrol 2022; 23:86. [PMID: 35246054 PMCID: PMC8895620 DOI: 10.1186/s12882-022-02712-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2021] [Accepted: 02/21/2022] [Indexed: 11/23/2022] Open
Abstract
Background Although metabolic acidosis is known as a potential complication of chronic kidney disease (CKD), there is limited information concerning the association between metabolic acidosis and clinical outcomes. Methods Five hundred fifty-two patients referred to renal division of Iwata City Hospital from 2015 to 2017 were included as a retrospective CKD cohort, and finally 178 patients with CKD stage III or IV and 20 to 80 years of age were analyzed. We examined the association between serum bicarbonate (HCO3−) levels and clinical outcomes using Kaplan-Meier methods after the matching of baseline characteristics by propensity scores. Results Of 178 patients with CKD, patients with lower HCO3− levels (N = 94), as compared with patients with higher HCO3− levels (N = 84), were more likely to be male (P < 0.05), had more severe CKD stages (P < 0.05), more frequent use of renin-angiotensin system inhibitor (P < 0.05) or uric acid lowering agent (P < 0.001), heavier body weight (P < 0.001) and lower estimated glomerular filtration rate (P < 0.05). In Kaplan-Meier analysis after propensity score matching, the incidence of composite outcome as the doubling of serum creatinine level from baseline, end-stage kidney disease requiring the initiation of dialysis, or death from any causes was significantly fewer in the higher HCO3− group than the lower HCO3− group (N = 57 each group, P = 0.016). Conclusions Lower HCO3− level is significantly associated with the doubling of serum creatinine level, end-stage kidney disease or all-cause mortality in patients with CKD. Trial registration This study was registered with the Clinical Trial Registry of the University Hospital Medical Information Network (http://www.umin.ac.jp/, study number: UMIN000044861).
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Affiliation(s)
- Hirotaka Fukasawa
- Renal Division, Department of Internal Medicine, Iwata City Hospital, 512-3 Ohkubo, Iwata, Shizuoka, 438-8550, Japan.
| | - Mai Kaneko
- Renal Division, Department of Internal Medicine, Iwata City Hospital, 512-3 Ohkubo, Iwata, Shizuoka, 438-8550, Japan
| | - Yuri Uchiyama
- Renal Division, Department of Internal Medicine, Iwata City Hospital, 512-3 Ohkubo, Iwata, Shizuoka, 438-8550, Japan
| | - Hideo Yasuda
- First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Ryuichi Furuya
- Renal Division, Department of Internal Medicine, Iwata City Hospital, 512-3 Ohkubo, Iwata, Shizuoka, 438-8550, Japan
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15
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Bushinsky DA, Krieger NS. Effects of Acid on Bone. Kidney Int 2022; 101:1160-1170. [DOI: 10.1016/j.kint.2022.02.032] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Revised: 02/25/2022] [Accepted: 02/28/2022] [Indexed: 12/11/2022]
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16
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Kaimori JY, Sakaguchi Y, Kajimoto S, Asahina Y, Oka T, Hattori K, Doi Y, Isaka Y. Diagnosing metabolic acidosis in chronic kidney disease: importance of blood pH and serum anion gap. Kidney Res Clin Pract 2022; 41:288-297. [PMID: 35172536 PMCID: PMC9184836 DOI: 10.23876/j.krcp.21.200] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2021] [Accepted: 10/18/2021] [Indexed: 12/05/2022] Open
Abstract
Metabolic acidosis is one of the most common complications of chronic kidney disease (CKD). It is associated with the progression of CKD, and many other functional impairments. Until recently, only serum bicarbonate levels have been used to evaluate acid-base changes in patients with reduced kidney function. However, recent emerging evidence suggests that nephrologists should reevaluate the clinical approach for diagnosing metabolic acidosis in patients with CKD based on two perspectives; pH and anion gap. Biochemistry and physiology textbooks clearly indicate that blood pH is the most important acid-base parameter for cellular function. Therefore, it is important to determine if the prognostic impact of hypobicarbonatemia varies according to pH level. A recent cohort study of CKD patients showed that venous pH modified the association between a low bicarbonate level and the progression of CKD. Furthermore, acidosis with a high anion gap has recently been recognized as an important prognostic factor, because veverimer, a nonabsorbable hydrochloride-binding polymer, has been shown to improve kidney function and decrease the anion gap. Acidosis with high anion gap frequently develops in later stages of CKD. Therefore, the anion gap is a time-varying factor and renal function (estimated glomerular filtration rate) is a time-dependent confounder for the anion gap and renal outcomes. Recent analyses using marginal structural models showed that acidosis with a high anion gap was associated with a high risk of CKD. Based on these observations, reconsideration of the clinical approach to diagnosing and treating metabolic acidosis in CKD may be warranted.
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Affiliation(s)
- Jun-Ya Kaimori
- Department of Inter-Organ Communication Research in Kidney Diseases, Osaka University Graduate School of Medicine, Osaka, Japan
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
- Correspondence: Jun-Ya Kaimori Department of Inter-Organ Communication Research in Kidney Diseases and Department of Nephrology, Osaka University Graduate School of Medicine, 2-2 Yamadaoka, Suita, Osaka 565-0871, Japan. E-mail:
| | - Yusuke Sakaguchi
- Department of Inter-Organ Communication Research in Kidney Diseases, Osaka University Graduate School of Medicine, Osaka, Japan
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Sachio Kajimoto
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yuta Asahina
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Tatsufumi Oka
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Koki Hattori
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yohei Doi
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Yoshitaka Isaka
- Department of Nephrology, Osaka University Graduate School of Medicine, Osaka, Japan
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Asahina Y, Sakaguchi Y, Kajimoto S, Hattori K, Doi Y, Oka T, Kaimori JY, Isaka Y. Time-updated anion gap and cardiovascular events in advanced CKD: a cohort study. Clin Kidney J 2021; 15:929-936. [PMID: 35498899 PMCID: PMC9050520 DOI: 10.1093/ckj/sfab277] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Indexed: 11/23/2022] Open
Abstract
Background Studies examining associations between metabolic acidosis and cardiovascular events in chronic kidney disease (CKD) have shown conflicting results and have not differentiated between normal anion gap (hyperchloremic) acidosis and high anion gap acidosis. We aimed to examine the impact of normal and high anion gap acidosis, separately, on the risk of cardiovascular events among patients with CKD. Methods This retrospective cohort study included 1168 patients with an estimated glomerular filtration rate (eGFR) of 10–60 mL/min/1.73 m2 and available data on anion gap. We analyzed the association of time-updated high anion gap (anion gap ≥9.2) with the rate of cardiovascular events using marginal structural models (MSMs) to account for time-dependent confounding. We also analyzed the association between time-updated normal anion gap acidosis (anion-gap-adjusted bicarbonate level ≤22.8 mEq/L) and cardiovascular events. Results The mean baseline eGFR of the cohort was 28 mL/min/1.73 m2. The prevalence rates of high anion gap in CKD stages G3a, G3b, G4 and G5 were 20%, 16%, 27% and 46%, respectively. During a median follow-up period of 2.9 years, 132 patients developed cardiovascular events (3.3/100 patient-years). In MSMs, high anion gap was associated with a higher rate of cardiovascular events [hazard ratio (HR) 1.87; 95% confidence interval (95% CI) 1.13‒3.09; P = 0.02] and the composite of cardiovascular events or all-cause death (HR 3.28; 95% CI 2.19‒4.91; P < 0.001). Normal anion gap acidosis was not associated with cardiovascular events (HR 0.74; 95% CI, 0.47‒1.17; P = 0.2). Conclusions Among patients with advanced CKD, high anion gap was associated with an increased risk of cardiovascular events.
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Affiliation(s)
- Yuta Asahina
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yusuke Sakaguchi
- Department of Inter-Organ Communication Research in Kidney Diseases, Osaka University Graduate School of Medicine, Suita, Japan
| | - Sachio Kajimoto
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Koki Hattori
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yohei Doi
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Tatsufumi Oka
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Jun-Ya Kaimori
- Department of Inter-Organ Communication Research in Kidney Diseases, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yoshitaka Isaka
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
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18
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Cheng F, Li Q, Wang J, Wang Z, Zeng F, Zhang Y. The Effects of Oral Sodium Bicarbonate on Renal Function and Cardiovascular Risk in Patients with Chronic Kidney Disease: A Systematic Review and Meta-Analysis. Ther Clin Risk Manag 2021; 17:1321-1331. [PMID: 34908841 PMCID: PMC8665881 DOI: 10.2147/tcrm.s344592] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2021] [Accepted: 11/30/2021] [Indexed: 11/23/2022] Open
Abstract
OBJECTIVE Oral sodium bicarbonate is often used to correct acid-base disturbance in patients with chronic kidney disease (CKD). However, there is little evidence on patient-level benign outcomes to support the practice. METHODS We conducted a systematic review and meta-analysis to examine the efficacy and safety of oral sodium bicarbonate in CKD patients. A total of 1853 patients with chronic metabolic acidosis or those with low-normal serum bicarbonate (22-24 mEq/L) were performed to compare the efficacy and safety of oral sodium bicarbonate in patients with CKD. RESULTS There was a significant increase in serum bicarbonate level (MD 2.37 mEq/L; 95% CI, 1.03 to 3.72) and slowed the decline in estimated glomerular filtration rate (eGFR) (MD -4.44 mL/min per 1.73 m2, 95% CI, -4.92 to -3.96) compared with the control groups. The sodium bicarbonate lowered T50-time, an indicator of vascular calcification (MD -20.74 min; 95% CI, -49.55 to 8.08); however, there was no significant difference between the two groups. In addition, oral sodium bicarbonate dramatically reduced systolic blood pressure (MD -2.97 mmHg; 95% CI, -5.04 to -0.90) and diastolic blood pressure (MD -1.26 mmHg; 95% CI, -2.33 to -0.19). There were no statistically significant body weight, urine pH and mean mid-arm muscle circumference. CONCLUSION Treatment of metabolic acidosis with sodium bicarbonate may slow the decline rate of kidney function and potentially significantly improve vascular endothelial function in patients with CKD. PROSPERO REGISTRATION NUMBER CRD42020207185.
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Affiliation(s)
- Fang Cheng
- Department of Pharmacy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China
- Hubei Province Clinical Research Center for Precision Medicine for Critical Illness, Wuhan, People’s Republic of China
| | - Qiang Li
- Department of Pharmacy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China
- Hubei Province Clinical Research Center for Precision Medicine for Critical Illness, Wuhan, People’s Republic of China
| | - Jinglin Wang
- Department of Pharmacy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China
- Hubei Province Clinical Research Center for Precision Medicine for Critical Illness, Wuhan, People’s Republic of China
| | - Zhendi Wang
- Department of Urology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China
| | - Fang Zeng
- Department of Pharmacy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China
- Hubei Province Clinical Research Center for Precision Medicine for Critical Illness, Wuhan, People’s Republic of China
| | - Yu Zhang
- Department of Pharmacy, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, People’s Republic of China
- Hubei Province Clinical Research Center for Precision Medicine for Critical Illness, Wuhan, People’s Republic of China
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19
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Bohling R, Grafals M, Moreau K, You Z, Tommerdahl KL, Bjornstad P, Stenson EK, Andrews E, Ramirez-Renteria L, Kendrick J. A Pilot Study of the Safety and Efficacy of Alkali Therapy on Vascular Function in Kidney Transplant Recipients. Kidney Int Rep 2021; 6:2323-2330. [PMID: 34514193 PMCID: PMC8419116 DOI: 10.1016/j.ekir.2021.06.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2021] [Revised: 05/18/2021] [Accepted: 06/07/2021] [Indexed: 12/31/2022] Open
Abstract
Introduction Metabolic acidosis is associated with cardiovascular events, graft function, and mortality in kidney transplant recipients (KTRs). We examined the effect of alkali therapy on vascular endothelial function in KTRs. Methods We performed an 18-week, randomized, double-blind, placebo-controlled crossover pilot study examining the effect of sodium bicarbonate therapy versus placebo on vascular function in 20 adult KTRs at least 1 year from transplant with an estimated glomerular filtration rate (eGFR) ≥45 ml/min per 1.73 m2 and a serum bicarbonate level of 20 to 26 mEq/L. Each treatment period was 8 weeks in duration with a 2-week washout period between treatments. The primary outcome was change in brachial artery flow-mediated dilation (FMD) between sodium bicarbonate treatment and placebo. Results Twenty patients completed the study and were included in the primary analysis. The mean (SD) baseline eGFR of participants was 75 (22) ml/min per 1.73 m2, respectively. Serum bicarbonate levels did not increase significantly with treatment (0.3 [1.5] mEq/L, P = 0.37). Sodium bicarbonate therapy was not associated with worsening blood pressure, weight gain, or hypokalemia. There was no significant increase in FMD after 8 weeks of sodium bicarbonate therapy compared to placebo (mean change in FMD 2.2%, 95% CI -0.1 to 4.6, P = 0.06). There were no significant changes in high-sensitivity C-reactive protein, interleukin-6, eGFR, or urinary albumin-to-creatinine ratio during treatment. Urinary ammonium excretion decreased by 9 mmol/d (P=0.003), with sodium bicarbonate. Conclusions Sodium bicarbonate therapy is safe and feasible in KTRs, and our results strengthen the need for a larger randomized controlled trial.
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Affiliation(s)
- Rachel Bohling
- Division of Renal Disease and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Monica Grafals
- Division of Renal Disease and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Kerrie Moreau
- Division of Geriatrics, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.,Eastern Colorado VA Geriatric Research, Education and Clinical Center, Aurora, Colorado, USA
| | - Zhiying You
- Division of Renal Disease and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Kalie L Tommerdahl
- Division of Renal Disease and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.,Department of Pediatrics, Section of Pediatric Endocrinology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Petter Bjornstad
- Division of Renal Disease and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA.,Department of Pediatrics, Section of Pediatric Endocrinology, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Erin K Stenson
- Department of Pediatrics, Section of Critical Care Medicine, Children's Hospital Colorado and University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Emily Andrews
- Division of Renal Disease and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Lorena Ramirez-Renteria
- Division of Renal Disease and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
| | - Jessica Kendrick
- Division of Renal Disease and Hypertension, University of Colorado Anschutz Medical Campus, Aurora, Colorado, USA
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20
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Abstract
Small-scale trials in patients with chronic kidney disease (CKD) 3-5 have shown that hypobicarbonatemic metabolic acidosis promotes progression of CKD. Accordingly, the 2012 KDIGO (Kidney Disease: Improving Global Outcomes) guideline suggests base administration to patients with CKD when serum bicarbonate concentration ([HCO3ˉ]) is <22 mEq/L (~15% of non–dialysis-dependent patients with CKD). However, individuals with milder CKD largely maintain serum [HCO3ˉ] within the normal range (eubicarbonatemia) and yet can manifest hydrogen ion (H+) retention. Limited data in eubicarbonatemic patients with CKD 2 suggest that base administration ameliorates CKD progression. Furthermore, most patients with moderate and advanced CKD maintain a normal serum [HCO3ˉ], and of those, the vast majority most likely harbor masked H+ retention. The present review probes this expanded concept of metabolic acidosis of CKD: the eubicarbonatemic H+ retention or subclinical metabolic acidosis of CKD. It focuses on the high prevalence of the entity, its pathophysiologic features, its clinical course, and recent work on potential biomarkers of the condition. Further, it puts forward the urgent task of investigating definitively whether treatment with alkali of eubicarbonatemic H+ retention delays CKD progression. If proven true, such knowledge would trigger a paradigm shift in the indication for alkali therapy in CKD.
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Affiliation(s)
- Nicolaos E Madias
- Department of Medicine, Tufts University School of Medicine and Division of Nephrology, Department of Medicine, St. Elizabeth's Medical Center, Boston, MA
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21
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Abstract
Acid-related injury from chronic metabolic acidosis is recognized through growing evidence of its deleterious effects, including kidney and other organ injury. Progressive acid accumulation precedes the signature manifestation of chronic metabolic acidosis, decreased plasma bicarbonate concentration. Acid accumulation that is not enough to manifest as metabolic acidosis, known as eubicarbonatemic acidosis, also appears to cause kidney injury, with exacerbated progression of CKD. Chronic engagement of mechanisms to mitigate the acid challenge from Western-type diets also appears to cause kidney injury. Rather than considering chronic metabolic acidosis as the only acid-related condition requiring intervention to reduce kidney injury, this review supports consideration of acid-related injury as a continuum. This "acid stress" continuum has chronic metabolic acidosis at its most extreme end, and high-acid-producing diets at its less extreme, yet detrimental, end.
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Affiliation(s)
- Donald E. Wesson
- Department of Internal Medicine, Texas A&M Health Science Center College of Medicine, Dallas, Texas
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22
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Admission Serum Bicarbonate Predicts Adverse Clinical Outcomes in Hospitalized Cirrhotic Patients. Can J Gastroenterol Hepatol 2021; 2021:9915055. [PMID: 34055676 PMCID: PMC8149247 DOI: 10.1155/2021/9915055] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Accepted: 05/05/2021] [Indexed: 01/11/2023] Open
Abstract
A low serum bicarbonate (SB) level is predictive of adverse outcomes in kidney injury, infection, and aging. Because the liver plays an important role in acid-base homeostasis and lactic acid metabolism, we speculated that such a relationship would exist for patients with cirrhosis. To assess the prognostic value of admission SB on adverse hospital outcomes, clinical characteristics were extracted and analyzed from a large electronic health record system. Patients were categorized based on admission SB (mEq/L) into 7 groups based on the reference range (22-25) into mildly (18-21), moderately (14-17), and severely (<14) decreased groups and mildly (26-29), moderately (30-33), and severely (>30) increased groups, and the relationship of SB category with the frequency of complications (acute kidney injury/hepatorenal syndrome, portosystemic encephalopathy, gastrointestinal bleeding, ascites, and spontaneous bacterial peritonitis) and hospital metrics (length of stay [LOS], admission to an intensive care unit [ICU], and mortality) was assessed. A total of 2,693 patients were analyzed. Mean SB was 22.9 ± 4.5 mEq/L. SB was within the normal range (22-25 mEq/L) in 1,072 (39.8%) patients, and 955 patients (36%) had a low SB. As the SB category decreased, the incidence of complications progressively increased (p < 0.001). Increased MELD-Na score and low serum albumin also correlated with frequency of complications (p < 0.001). As the SB category decreased, LOS, ICU admission, and mortality progressively increased (p < 0.001). On multivariate analysis, the association of decreased SB with higher odds of complications, LOS, ICU admission, and mortality persisted. Conclusion. Low admission SB in patients with cirrhosis is associated with cirrhotic complications, longer LOS, increased ICU admissions, and increased hospital mortality.
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Abstract
Metabolic acidosis is fairly common in patients with chronic kidney disease (CKD). The prevalence of metabolic acidosis increases with worsening kidney function and is observed in ∼40% of those with stage 4 CKD. For the past 2 decades, clinical practice guidelines have suggested treatment of metabolic acidosis to counterbalance adverse effects of metabolic acidosis on bone and muscle. Studies in animal models of CKD also demonstrated that metabolic acidosis causes kidney fibrosis. During the past decade, results from observational studies identified associations between metabolic acidosis and adverse kidney outcomes, and results from interventional studies support the hypothesis that treating metabolic acidosis with sodium bicarbonate preserves kidney function. However, convincing data from large-scale, double-blinded, placebo-controlled, randomized trials have been lacking. This review discusses findings from recent interventional trials of alkali therapy in CKD and new findings linking metabolic acidosis with cardiovascular disease in adults and CKD progression in children. Finally, a novel agent that treats metabolic acidosis in patients with CKD by binding hydrochloric acid in the gastrointestinal tract is discussed.
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Affiliation(s)
- Michal L Melamed
- Department of Medicine, Albert Einstein College of Medicine/Montefiore Medical Center, Bronx, NY
| | - Kalani L Raphael
- Division of Nephrology & Hypertension, Department of Medicine, Oregon Health & Science University and Portland VA Medical Center, Portland, OR
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24
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Bovée DM, Cuevas CA, Zietse R, Danser AHJ, Mirabito Colafella KM, Hoorn EJ. Salt-sensitive hypertension in chronic kidney disease: distal tubular mechanisms. Am J Physiol Renal Physiol 2020; 319:F729-F745. [DOI: 10.1152/ajprenal.00407.2020] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Chronic kidney disease (CKD) causes salt-sensitive hypertension that is often resistant to treatment and contributes to the progression of kidney injury and cardiovascular disease. A better understanding of the mechanisms contributing to salt-sensitive hypertension in CKD is essential to improve these outcomes. This review critically explores these mechanisms by focusing on how CKD affects distal nephron Na+ reabsorption. CKD causes glomerulotubular imbalance with reduced proximal Na+ reabsorption and increased distal Na+ delivery and reabsorption. Aldosterone secretion further contributes to distal Na+ reabsorption in CKD and is not only mediated by renin and K+ but also by metabolic acidosis, endothelin-1, and vasopressin. CKD also activates the intrarenal renin-angiotensin system, generating intratubular angiotensin II to promote distal Na+ reabsorption. High dietary Na+ intake in CKD contributes to Na+ retention by aldosterone-independent activation of the mineralocorticoid receptor mediated through Rac1. High dietary Na+ also produces an inflammatory response mediated by T helper 17 cells and cytokines increasing distal Na+ transport. CKD is often accompanied by proteinuria, which contains plasmin capable of activating the epithelial Na+ channel. Thus, CKD causes both local and systemic changes that together promote distal nephron Na+ reabsorption and salt-sensitive hypertension. Future studies should address remaining knowledge gaps, including the relative contribution of each mechanism, the influence of sex, differences between stages and etiologies of CKD, and the clinical relevance of experimentally identified mechanisms. Several pathways offer opportunities for intervention, including with dietary Na+ reduction, distal diuretics, renin-angiotensin system inhibitors, mineralocorticoid receptor antagonists, and K+ or H+ binders.
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Affiliation(s)
- Dominique M. Bovée
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
- Division of Vascular Medicine, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Catharina A. Cuevas
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Robert Zietse
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - A. H. Jan Danser
- Division of Vascular Medicine, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
| | - Katrina M. Mirabito Colafella
- Cardiovascular Disease Program, Monash Biomedicine Discovery Institute, Monash University, Melbourne, Victoria, Australia
- Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - Ewout J. Hoorn
- Division of Nephrology and Transplantation, Department of Internal Medicine, Erasmus MC, Erasmus University Medical Center, Rotterdam, The Netherlands
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Ritter A, Mohebbi N. Causes and Consequences of Metabolic Acidosis in Patients after Kidney Transplantation. Kidney Blood Press Res 2020; 45:792-801. [PMID: 33040055 DOI: 10.1159/000510158] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 07/01/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Metabolic acidosis (MA) is a common complication in kidney transplantation (KTx). It is more prevalent in KTx than in CKD, and it occurs at higher glomerular filtration rates. The pathophysiologic understanding of MA in KTx and its clinical impact has been highlighted by few recent studies. However, no guidelines exist yet for the treatment of MA after KTx. SUMMARY MA in KTx seems to share pathophysiologic mechanisms with CKD, such as impaired ammoniagenesis. Additional kidney transplant-specific factors seem to alter not only the prevalence but also the phenotype of MA, which typically shows features of renal tubular acidosis. There is evidence that calcineurin inhibitors, immunological factors, process of donation, donor characteristics, and diet may contribute to MA occurrence. According to several mainly observational studies, MA seems to play a role in disturbed bone metabolism, cardiovascular morbidity, declining graft function, and mortality. A better understanding of the pathophysiology and evidence from randomized controlled trials, in particular, are needed to clarify the role of MA and the potential benefit of alkali treatment in KTx. Alkali therapy might not only be beneficial but also cost effective and safe. Key Messages: MA seems to be associated with several negative outcomes in KTx. A deeper understanding of the pathophysiology and clinical consequences of MA in KTx is crucial. Clinical trials will have to determine the potential benefits of alkali therapy.
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Affiliation(s)
- Alexander Ritter
- Division of Nephrology, University Hospital of Zurich, Zurich, Switzerland
| | - Nilufar Mohebbi
- Division of Nephrology, University Hospital of Zurich, Zurich, Switzerland, .,Praxis und Dialysezentrum Zürich-City, Zurich, Switzerland,
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Kajimoto S, Sakaguchi Y, Asahina Y, Kaimori JY, Isaka Y. Modulation of the Association of Hypobicarbonatemia and Incident Kidney Failure With Replacement Therapy by Venous pH: A Cohort Study. Am J Kidney Dis 2020; 77:35-43. [PMID: 32828983 DOI: 10.1053/j.ajkd.2020.06.019] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2020] [Accepted: 06/22/2020] [Indexed: 01/01/2023]
Abstract
RATIONALE & OBJECTIVE Studies showing an association between lower bicarbonate levels and worse kidney disease prognosis have not accounted for the influence of pH. It remains unknown whether this association is consistent across a wide range of blood pH values. This study sought to assess how pH modifies the relationship between hypobicarbonatemia and incident kidney failure requiring kidney replacement therapy (KFRT). STUDY DESIGN Retrospective cohort study. SETTING & PARTICIPANTS 1,058 Japanese patients with estimated glomerular filtration rates<60mL/min/1.73m2. EXPOSURE Baseline venous bicarbonate levels and venous pH. OUTCOME KFRT defined as initiation of kidney replacement therapy (hemodialysis, peritoneal dialysis, and kidney transplantation). ANALYTICAL APPROACH Cox proportional hazards model assessing the interaction between baseline bicarbonate levels and venous pH on incident KFRT. RESULTS In the lowest bicarbonate quartile (≤21.5 mEq/L), 59% of patients had acidemia (pH<7.32), whereas 38% had venous pH within the normal range and 3% had alkalemia (pH>7.42). During a median follow-up of 3.0 years, 374 patients developed KFRT. Venous pH modified the association between bicarbonate level and rate of KFRT (P for interaction=0.04). After adjustment for potential confounders, including capacity for respiratory compensation, the lowest (vs the highest) bicarbonate quartile was associated with a 2.29-fold (95% CI, 1.10-4.77; P=0.03) higher rate of KFRT among patients with acidemia (pH<7.32). In contrast, among patients without acidemia (pH≥7.32), no significant association was found between bicarbonate level and KFRT. In an exploratory analysis, patients with higher respiratory compensation capacity had a lower rate of KFRT (HR per 0.1 increase in respiratory compensation capacity, 0.90; 95% CI, 0.87-0.94; P<0.001). LIMITATIONS Observational study design; blood gas measurements were performed in a select patient population. CONCLUSIONS Venous pH modified the association of hypobicarbonatemia with progression of chronic kidney disease to KFRT. Measurement of venous pH may be valuable for identifying patients with chronic kidney disease and hypobicarbonatemia and may inform treatment.
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Affiliation(s)
- Sachio Kajimoto
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yusuke Sakaguchi
- Department of Inter-Organ Communication Research in Kidney Diseases, Osaka University Graduate School of Medicine, Suita, Japan
| | - Yuta Asahina
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
| | - Jun-Ya Kaimori
- Department of Inter-Organ Communication Research in Kidney Diseases, Osaka University Graduate School of Medicine, Suita, Japan.
| | - Yoshitaka Isaka
- Department of Nephrology, Osaka University Graduate School of Medicine, Suita, Japan
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Clinical evidence that treatment of metabolic acidosis slows the progression of chronic kidney disease. Curr Opin Nephrol Hypertens 2020; 28:267-277. [PMID: 30681417 PMCID: PMC6467553 DOI: 10.1097/mnh.0000000000000491] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
PURPOSE OF REVIEW We review the growing clinical evidence that metabolic acidosis mediates chronic kidney disease (CKD) progression and that treatment to increase the associated low serum bicarbonate (HCO3) in CKD is disease-modifying. RECENT FINDINGS Seven prospective studies of patients with wide ranges of estimated glomerular filtration rates (eGFRs) and serum HCO3 examined the effect on CKD of increasing serum HCO3 using dietary acid reduction with either oral alkali (sodium bicarbonate or sodium citrate), a vegetarian diet very low in acid-producing protein (0.3 g/kg/day) supplemented with ketoanalogues or added base-producing fruits and vegetables. Clinical outcomes included slower kidney function decline (using eGFR measurements) and fewer patients progressing to end-stage kidney disease. Post hoc analyses demonstrated that: treatment of metabolic acidosis for 2 years decreased the number of patients with at least a 40% eGFR decline, a validated surrogate for progression to end-stage kidney disease and across four studies, treatment to increase serum HCO3 by 4-6.8 mEq/l in acidotic patients with CKD was associated with a ∼4 ml/min/1.73 m reduction in the rate of eGFR decline over 6-24 months compared with controls. SUMMARY Metabolic acidosis appears to enhance CKD progression and its treatment should be studied further as a potential disease-modifying intervention.
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Wesson DE, Buysse JM, Bushinsky DA. Mechanisms of Metabolic Acidosis-Induced Kidney Injury in Chronic Kidney Disease. J Am Soc Nephrol 2020; 31:469-482. [PMID: 31988269 DOI: 10.1681/asn.2019070677] [Citation(s) in RCA: 104] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Retrospective analyses and single-center prospective studies identify chronic metabolic acidosis as an independent and modifiable risk factor for progression of CKD. In patients with CKD, untreated chronic metabolic acidosis often leads to an accelerated reduction in GFR. Mechanisms responsible for this reduction include adaptive responses that increase acid excretion but lead to a decline in kidney function. Metabolic acidosis in CKD stimulates production of intrakidney paracrine hormones including angiotensin II, aldosterone, and endothelin-1 (ET-1) that mediate the immediate benefit of increased kidney acid excretion, but their chronic upregulation promotes inflammation and fibrosis. Chronic metabolic acidosis also stimulates ammoniagenesis that increases acid excretion but also leads to ammonia-induced complement activation and deposition of C3 and C5b-9 that can cause tubule-interstitial damage, further worsening disease progression. These effects, along with acid accumulation in kidney tissue, combine to accelerate progression of kidney disease. Treatment of chronic metabolic acidosis attenuates these adaptive responses; reduces levels of angiotensin II, aldosterone, and ET-1; reduces ammoniagenesis; and diminishes inflammation and fibrosis that may lead to slowing of CKD progression.
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Affiliation(s)
- Donald E Wesson
- Baylor Scott & White Health and Wellness Center, Dallas, Texas; .,Department of Internal Medicine, Texas A&M College of Medicine, Bryan, Texas
| | | | - David A Bushinsky
- Division of Nephrology, University of Rochester School of Medicine, Rochester, New York
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Raphael KL, Greene T, Wei G, Bullshoe T, Tuttle K, Cheung AK, Beddhu S. Sodium Bicarbonate Supplementation and Urinary TGF- β1 in Nonacidotic Diabetic Kidney Disease: A Randomized, Controlled Trial. Clin J Am Soc Nephrol 2020; 15:200-208. [PMID: 31974286 PMCID: PMC7015087 DOI: 10.2215/cjn.06600619] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2019] [Accepted: 12/10/2019] [Indexed: 01/09/2023]
Abstract
BACKGROUND AND OBJECTIVES In early-phase studies of individuals with hypertensive CKD and normal serum total CO2, sodium bicarbonate reduced urinary TGF-β1 levels and preserved kidney function. The effect of sodium bicarbonate on kidney fibrosis and injury markers in individuals with diabetic kidney disease and normal serum total CO2 is unknown. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS We conducted a randomized, double-blinded, placebo-controlled study in 74 United States veterans with type 1 or 2 diabetes mellitus, eGFR of 15-89 ml/min per 1.73 m2, urinary albumin-to-creatinine ratio (UACR) ≥30 mg/g, and serum total CO2 of 22-28 meq/L. Participants received oral sodium bicarbonate (0.5 meq/kg lean body wt per day; n=35) or placebo (n=39) for 6 months. The primary outcome was change in urinary TGF-β1-to-creatinine from baseline to months 3 and 6. Secondary outcomes included changes in urinary kidney injury molecule-1 (KIM-1)-to-creatinine, fibronectin-to-creatinine, neutrophil gelatinase-associated lipocalin (NGAL)-to-creatinine, and UACR from baseline to months 3 and 6. RESULTS Key baseline characteristics were age 72±8 years, eGFR of 51±18 ml/min per 1.73 m2, and serum total CO2 of 24±2 meq/L. Sodium bicarbonate treatment increased mean total CO2 by 1.2 (95% confidence interval [95% CI], 0.3 to 2.1) meq/L, increased urinary pH by 0.6 (95% CI, 0.5 to 0.8), and decreased urinary ammonium excretion by 5 (95% CI, 0 to 11) meq/d and urinary titratable acid excretion by 11 (95% CI, 5 to 18) meq/d. Sodium bicarbonate did not significantly change urinary TGF-β1/creatinine (difference in change, 13%, 95% CI, -10% to 40%; change within the sodium bicarbonate group, 8%, 95% CI, -10% to 28%; change within the placebo group, -4%, 95% CI, -19% to 13%). Similarly, no significant effect on KIM-1-to-creatinine (difference in change, -10%, 95% CI, -38% to 31%), fibronectin-to-creatinine (8%, 95% CI, -15% to 37%), NGAL-to-creatinine (-33%, 95% CI, -56% to 4%), or UACR (1%, 95% CI, -25% to 36%) was observed. CONCLUSIONS In nonacidotic diabetic kidney disease, sodium bicarbonate did not significantly reduce urinary TGF-β1, KIM-1, fibronectin, NGAL, or UACR over 6 months.
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Affiliation(s)
- Kalani L Raphael
- Medicine Section, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah; and .,Department of Internal Medicine, University of Utah Health, Salt Lake City, Utah
| | - Tom Greene
- Department of Internal Medicine, University of Utah Health, Salt Lake City, Utah
| | - Guo Wei
- Department of Internal Medicine, University of Utah Health, Salt Lake City, Utah
| | - Tristin Bullshoe
- Department of Internal Medicine, University of Utah Health, Salt Lake City, Utah
| | - Kunani Tuttle
- Department of Internal Medicine, University of Utah Health, Salt Lake City, Utah
| | - Alfred K Cheung
- Medicine Section, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah; and.,Department of Internal Medicine, University of Utah Health, Salt Lake City, Utah
| | - Srinivasan Beddhu
- Medicine Section, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah; and.,Department of Internal Medicine, University of Utah Health, Salt Lake City, Utah
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Novel dietary and pharmacologic approaches for acid–base modulation to preserve kidney function and manage uremia. Curr Opin Nephrol Hypertens 2020; 29:39-48. [DOI: 10.1097/mnh.0000000000000568] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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31
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Dong Y, Qu X, Wu G, Luo X, Tang B, Wu F, Fan L, Dev S, Liang T. Advances in the Detection, Mechanism and Therapy of Chronic Kidney Disease. Curr Pharm Des 2019; 25:4235-4250. [PMID: 31742493 DOI: 10.2174/1381612825666191119094354] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2019] [Accepted: 10/30/2019] [Indexed: 01/08/2023]
Abstract
Chronic Kidney Disease (CKD) is characterized by the gradual loss of renal mass and functions. It has become a global health problem, with hundreds of millions of people being affected. Both its incidence and prevalence are increasing over time. More than $20,000 are spent on each patient per year. The economic burden on the patients, as well as the society, is heavy and their life quality worsen over time. However, there are still limited effective therapeutic strategies for CKD. Patients mainly rely on dialysis and renal transplantation, which cannot prevent all the complications of CKD. Great efforts are needed in understanding the nature of CKD progression as well as developing effective therapeutic methods, including pharmacological agents. This paper reviews three aspects in the research of CKD that may show great interests to those who devote to bioanalysis, biomedicine and drug development, including important endogenous biomarkers quantification, mechanisms underlying CKD progression and current status of CKD therapy.
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Affiliation(s)
- Yu Dong
- Department of Urology, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, 530011, Nanning, China
| | - Xiaosheng Qu
- National Engineering Laboratory of Southwest Endangered Medicinal Resources Development, Guangxi Botanical Garden of Medicinal Plants, No. 189, Changgang Road, 530023, Nanning, China
| | - Gang Wu
- Department of Urology, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, 530011, Nanning, China
| | - Xiangdong Luo
- Department of Urology, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, 530011, Nanning, China
| | - Botao Tang
- Department of Urology, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, 530011, Nanning, China
| | - Fangfang Wu
- National Engineering Laboratory of Southwest Endangered Medicinal Resources Development, Guangxi Botanical Garden of Medicinal Plants, No. 189, Changgang Road, 530023, Nanning, China
| | - Lanlan Fan
- School of Pharmacy, Guangxi University of Chinese Medicine, 530001, Nanning, China
| | - Sooranna Dev
- Department of Surgery and Cancer, Imperial College London, Chelsea and Westminster Hospital, 369, Fulham Road, London SW10 9NH, United Kingdom
| | - Taisheng Liang
- Department of Urology, Ruikang Hospital Affiliated to Guangxi University of Chinese Medicine, 530011, Nanning, China
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Cochat P, Febvey O, Bacchetta J, Bérard E, Cabrera N, Dubourg L. Towards adulthood with a solitary kidney. Pediatr Nephrol 2019; 34:2311-2323. [PMID: 30276534 DOI: 10.1007/s00467-018-4085-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/09/2018] [Revised: 08/03/2018] [Accepted: 09/10/2018] [Indexed: 02/07/2023]
Abstract
Around 1/1000 people have a solitary kidney. Congenital conditions mainly include multicystic dysplastic kidney and unilateral renal aplasia/agenesis; acquired conditions are secondary to nephrectomy performed because of urologic structural abnormalities, severe parenchymal infection, renal trauma, and renal or pararenal tumors. Children born with congenital solitary kidney have a better long-term glomerular filtration rate than those with solitary kidney secondary to nephrectomy later in life. Acute and chronic adaptation processes lead to hyperfiltration followed by fibrosis in the remnant kidney, with further risk of albuminuria, arterial hypertension, and impaired renal function. Protective measures rely on non-pharmacological renoprotection (controlled protein and sodium intake, avoidance/limitation of nephrotoxic agents, keeping normal body mass index, and limitation of tobacco exposure). Lifelong monitoring should include blood pressure and albuminuria assessment, completed by glomerular filtration rate (GFR) estimation in case of abnormal values. In the absence of additional risk factors to solitary kidney, such assessment can be proposed every 5 years. There is no current consensus for indication and timing of pharmacological intervention.
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Affiliation(s)
- Pierre Cochat
- Centre de référence des maladies rénales rares Néphrogones, Hospices Civils de Lyon, Lyon, France.
- EPICIME Epidémiologie Pharmacologie Investigation Clinique Information Médicale de l'Enfant, Hospices Civils de Lyon, Lyon, France.
- Université Claude-Bernard Lyon 1, Lyon, France.
- Service de Néphrologie Rhumatologie Dermatologie Pédiatriques, Hôpital Femme Mère Enfant, 59 Boulevard Pinel, 69677, Bron Cedex, France.
| | - Olivia Febvey
- EPICIME Epidémiologie Pharmacologie Investigation Clinique Information Médicale de l'Enfant, Hospices Civils de Lyon, Lyon, France
| | - Justine Bacchetta
- Centre de référence des maladies rénales rares Néphrogones, Hospices Civils de Lyon, Lyon, France
- EPICIME Epidémiologie Pharmacologie Investigation Clinique Information Médicale de l'Enfant, Hospices Civils de Lyon, Lyon, France
- Université Claude-Bernard Lyon 1, Lyon, France
| | | | - Natalia Cabrera
- Centre de référence des maladies rénales rares Néphrogones, Hospices Civils de Lyon, Lyon, France
| | - Laurence Dubourg
- Centre de référence des maladies rénales rares Néphrogones, Hospices Civils de Lyon, Lyon, France
- Université Claude-Bernard Lyon 1, Lyon, France
- Exploration fonctionnelle rénale, Hospices Civils de Lyon, Lyon, France
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Di Iorio BR, Bellasi A, Raphael KL, Santoro D, Aucella F, Garofano L, Ceccarelli M, Di Lullo L, Capolongo G, Di Iorio M, Guastaferro P, Capasso G. Treatment of metabolic acidosis with sodium bicarbonate delays progression of chronic kidney disease: the UBI Study. J Nephrol 2019; 32:989-1001. [PMID: 31598912 PMCID: PMC6821658 DOI: 10.1007/s40620-019-00656-5] [Citation(s) in RCA: 88] [Impact Index Per Article: 17.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2019] [Accepted: 09/28/2019] [Indexed: 11/27/2022]
Abstract
Background Metabolic acidosis is associated with accelerated progression of chronic kidney disease (CKD). Whether treatment of metabolic acidosis with sodium bicarbonate improves kidney and patient survival in CKD is unclear. Methods We conducted a randomized (ratio 1:1). open-label, controlled trial (NCT number: NCT01640119. www.clinicaltrials.gov) to determine the effect in patients with CKD stage 3–5 of treatment of metabolic acidosis with sodium bicarbonate (SB) on creatinine doubling (primary endpoint), all-cause mortality and time to renal replacement therapy compared to standard care (SC) over 36-months. Parametric, non-parametric tests and survival analyses were used to assess the effect of SB on these outcomes. Results A total of 376 and 364 individuals with mean (SD) age 67.8 (14.9) years, creatinine clearance 30 (12) ml/min, and serum bicarbonate 21.5 (2.4) mmol/l were enrolled in SB and SC, respectively. Mean (SD) follow-up was 29.6 (9.8) vs 30.3 (10.7) months in SC and SB. respectively. The mean (SD) daily doses of SB was 1.13 (0.10). 1.12 (0.11). and 1.09 (0.12) mmol/kg*bw/day in the first, second and third year of follow-up, respectively. A total of 87 participants reached the primary endpoint [62 (17.0%) in SC vs 25 (6.6%) in SB, p < 0.001). Similarly, 71 participants [45 (12.3%) in SC and 26 (6.9%) in SB, p = 0.016] started dialysis while 37 participants [25 (6.8%) in SC and 12 (3.1%) in SB, p = 0.004] died. There were no significant effect of SB on blood pressure, total body weight or hospitalizations. Conclusion In persons with CKD 3–5 without advanced stages of chronic heart failure, treatment of metabolic acidosis with sodium bicarbonate is safe and improves kidney and patient survival. Electronic supplementary material The online version of this article (10.1007/s40620-019-00656-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Biagio R Di Iorio
- Nephrology and Dialysis Unit, PO "A. Landolfi", Solofra, Avellino, Italy.
- Nephrology and Dialysis, "Antonio Cardarelli" hospital, Naples, Italia.
| | - Antonio Bellasi
- Department of Research, Innovation, Brand Reputation, Bergamo Hospital, ASST Papa Giovanni XXIII, Bergamo, Italy
| | - Kalani L Raphael
- Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah Health, Salt Lake City, UT, USA
| | - Domenico Santoro
- Dialysis and Nephrology Unit, University of Messina, Messina, Italy
| | - Filippo Aucella
- Department of Nephrology and Dialysis, IRCCS "Casa Sollievo della Sofferenza", San Giovanni Rotondo, Foggia, Italy
| | - Luciano Garofano
- Biogem, Section of Genetic and Translational Medicine, Ariano Irpino, Avellino, Italy
| | - Michele Ceccarelli
- Biogem, Section of Genetic and Translational Medicine, Ariano Irpino, Avellino, Italy
- Department of Science and Technology, University of Sannio, Benevento, Italy
| | - Luca Di Lullo
- Department of Nephrology and Dialysis, "L. Parodi-Delfino" Hospital, Colleferro, Roma, Italy
| | - Giovanna Capolongo
- Department of Translational Medical Sciences, University of Campania "Luigi Vanvitelli", Naples, Italy
| | - Mattia Di Iorio
- Data Scientist, Landolfi Nephrology Dialysis Consultant, Solofra, Avellino, Italy
| | - Pasquale Guastaferro
- Department of Nephrology, "G. Criscuoli" Hospital, Sant'Angelo dei Lombardi, Avellino, Italia
| | - Giovambattista Capasso
- Department of Nephrology and Dialysis, IRCCS "Casa Sollievo della Sofferenza", San Giovanni Rotondo, Foggia, Italy
- Department of Translational Medical Sciences, University of Campania "Luigi Vanvitelli", Naples, Italy
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Navaneethan SD, Shao J, Buysse J, Bushinsky DA. Effects of Treatment of Metabolic Acidosis in CKD: A Systematic Review and Meta-Analysis. Clin J Am Soc Nephrol 2019; 14:1011-1020. [PMID: 31196951 PMCID: PMC6625635 DOI: 10.2215/cjn.13091118] [Citation(s) in RCA: 75] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2018] [Accepted: 05/04/2019] [Indexed: 01/18/2023]
Abstract
BACKGROUND AND OBJECTIVES Metabolic acidosis is associated with progression of CKD and has significant adverse effects on muscle and bone. A systematic review and meta-analysis was conducted to evaluate the benefits and risks of metabolic acidosis treatment with oral alkali supplementation or a reduction of dietary acid intake in those with CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS MEDLINE, Embase, and Cochrane CENTRAL were searched for relevant trials in patients with stage 3-5 CKD and metabolic acidosis (<22 mEq/L) or low-normal serum bicarbonate (22-24 mEq/L). Data were pooled in a meta-analysis with results expressed as weighted mean difference for continuous outcomes and relative risk for categorical outcomes with 95% confidence intervals (95% CIs), using a random effects model. Study quality and strength of evidence were assessed using Cochrane risk of bias and the Grading of Recommendations Assessment, Development and Evaluation criteria. RESULTS Fourteen clinical trials were included (n=1394 participants). Treatment of metabolic acidosis with oral alkali supplementation or a reduction of dietary acid intake increased serum bicarbonate levels (14 studies, 1378 patients, mean difference 3.33 mEq/L, 95% CI, 2.37 to 4.29) and resulted in a slower decline in eGFR (13 studies, 1329 patients, mean difference -3.28 ml/min per 1.73 m2, 95% CI, -4.42 to -2.14; moderate certainty) and a reduction in urinary albumin excretion (very-low certainty), along with a reduction in the risk of progression to ESKD (relative risk, 0.32; 95% CI, 0.18 to 0.56; low certainty). Oral alkali supplementation was associated with worsening hypertension or the requirement for increased antihypertensive therapy (very-low certainty). CONCLUSIONS Low-to-moderate certainty evidence suggest that oral alkali supplementation or a reduction in dietary acid intake may slow the rate of kidney function decline and potentially reduce the risk of ESKD in patients with CKD and metabolic acidosis.
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Affiliation(s)
- Sankar D. Navaneethan
- Section of Nephrology, Department of Medicine, Baylor College of Medicine, Houston, Texas
| | - Jun Shao
- Tricida, Inc., South San Francisco, CA; and
| | | | - David A. Bushinsky
- Division of Nephrology, Department of Medicine, University of Rochester School of Medicine and Dentistry, Rochester, New York
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Goraya N, Simoni J, Sager LN, Mamun A, Madias NE, Wesson DE. Urine citrate excretion identifies changes in acid retention as eGFR declines in patients with chronic kidney disease. Am J Physiol Renal Physiol 2019; 317:F502-F511. [PMID: 31215805 DOI: 10.1152/ajprenal.00044.2019] [Citation(s) in RCA: 27] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Previous studies have shown that acid (H+) retention in patients with chronic kidney disease (CKD) but without metabolic acidosis increases as the estimated glomerular filtration rate (eGFR) decreases over time. The present study examined whether changes in urine excretion of the pH-sensitive metabolite citrate predicted changes in H+ retention over time in similar patients with CKD that were followed for 10 yr. We randomized 120 CKD2 nondiabetic, hypertension-associated nephropathy patients with plasma total CO2 of >24 mM to receive 0.5 meq·kg body wt-1·day-1 NaHCO3 ([Formula: see text]; n = 40), 0.5 meq·kg body wt-1·day-1 NaCl (NaCl; n = 40), or usual care (UC; n = 40). We assessed eGFR (CKD-EPI) and H+ retention by comparing the observed with expected plasma total CO2 increase 2 h after an oral NaHCO3 bolus (0.5 meq/kg body wt). Although 10 yr versus baseline eGFR was lower for each group, 10-yr eGFR was higher (P < 0.01) in [Formula: see text] (59.6 ± 4.8 ml·min-1·1.73 m-2) than NaCl and UC (52.1 ± 5.9 and 52.3 ± 4.1 ml·min-1·1.73 m-2, respectively) groups. Less eGFR preservation was associated with higher 10-yr versus baseline H+ retention in the NaCl group (26.5 ± 13.1 vs. 18.2 ± 15.3 mmol, P < 0.01) and UC group (24.8 ± 11.3 vs. 17.7 ± 10.9 mmol, P < 0.01) and with lower 10-yr versus baseline 8-h urine citrate excretion (UcitrateV) for the NaCl group (162 ± 47 vs. 196 ± 52 mg, respectively, P < 0.01) and UC group (153 ± 41 vs. 186 ± 42 mg, respectively, P < 0.01). Conversely, better eGFR preservation in the [Formula: see text] group was associated with no differences in 10-yr versus baseline H+ retention (14.2 ±13.5 vs. 16.1 ± 15.1 mmol, P = 1.00) or UcitrateV (212 ± 45 vs. 203 ± 49 mg, respectively, P = 0.74). An overall generalized linear model for repeated measures showed that UcitrateV predicted H+ retention (P < 0.01). Less eGFR preservation in patients with CKD2 without metabolic acidosis was associated with increased H+ retention that was predicted by decreased UcitrateV.
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Affiliation(s)
- Nimrit Goraya
- Baylor Scott and White Health Department of Internal Medicine, Temple, Texas.,Texas A&M Health Sciences Center, College of Medicine, Temple Texas
| | - Jan Simoni
- Department of Surgery, Texas Tech University Health Sciences Center, Lubbock, Texas
| | - Lauren N Sager
- Baylor Scott and White Health Department of Biostatistics, Temple, Texas
| | - Abdullah Mamun
- Baylor Scott and White Health and Wellness Center, Dallas, Texas
| | - Nicolaos E Madias
- School of Medicine, Department of Medicine, St. Elizabeth's Medical Center and Tufts University, Boston, Massachusetts
| | - Donald E Wesson
- Baylor Scott and White Health Department of Internal Medicine, Dallas, Texas.,Texas A&M Health Sciences Center, College of Medicine, Dallas, Texas
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Banerjee T, Crews DC, Wesson DE, McCulloch CE, Johansen KL, Saydah S, Rios Burrows N, Saran R, Gillespie B, Bragg-Gresham J, Powe NR. Elevated serum anion gap in adults with moderate chronic kidney disease increases risk for progression to end-stage renal disease. Am J Physiol Renal Physiol 2019; 316:F1244-F1253. [PMID: 30908932 PMCID: PMC6620593 DOI: 10.1152/ajprenal.00496.2018] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2018] [Revised: 03/08/2019] [Accepted: 03/19/2019] [Indexed: 01/13/2023] Open
Abstract
Acid retention associated with reduced glomerular filtration rate (GFR) exacerbates nephropathy progression in partial nephrectomy models of chronic kidney disease (CKD) and might be reflected in patients with CKD with reduced estimated GFR (eGFR) by increased anion gap (AG). We explored the presence of AG and its association with CKD in 14,924 adults aged ≥20 yr with eGFR ≥ 15 ml·min-1·1.73 m-2 enrolled in the National Health and Nutrition Examination Survey III, 1988-1994, using multivariable regression analysis. The model was adjusted for sociodemographic characteristics, diabetes, and hypertension. We further examined the association between AG and incident end-stage renal disease (ESRD) using frailty models, adjusting for demographics, clinical factors, body mass index, serum albumin, bicarbonate, eGFR, and urinary albumin-to-creatinine ratio by following 558 adults with moderate CKD for 12 yr via the United States Renal Data System. Laboratory measures determined AG using the traditional, albumin-corrected, and full AG definitions. Individuals with moderate CKD (eGFR: 30-59 ml·min-1·1.73 m-2) had a greater AG than those with eGFR ≥ 60 ml·min-1·1.73 m-2 in multivariable regression analysis with adjustment for covariates. We found a graded relationship between the adjusted mean for all three definitions of AG and eGFR categories (P trend < 0.0001). During followup, 9.2% of adults with moderate CKD developed ESRD. Those with AG in the highest tertile had a higher risk of ESRD after adjusting for covariates in a frailty model [relative hazard (95% confidence interval) for traditional AG: 1.76 (1.16-2.32)] compared with those in the middle tertile. The data suggest that high AG, even after adjusting for serum bicarbonate, is a contributing acid-base mechanism to CKD progression in adults with moderate chronic kidney disease.
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Affiliation(s)
- Tanushree Banerjee
- Division of General Internal Medicine, Department of Medicine, University of California , San Francisco, California
| | - Deidra C Crews
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine , Baltimore, Maryland
- Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, Maryland
| | - Donald E Wesson
- Baylor Scott & White Health and Wellness Center , Dallas, Texas
| | - Charles E McCulloch
- Department of Biostatistics, University of California , San Francisco, California
| | - Kirsten L Johansen
- Division of Nephrology, Department of Medicine, University of California , San Francisco, California
| | - Sharon Saydah
- Division of Diabetes Translation, Centers of Disease and Control and Prevention , Atlanta, Georgia
| | - Nilka Rios Burrows
- Division of Diabetes Translation, Centers of Disease and Control and Prevention , Atlanta, Georgia
| | - Rajiv Saran
- Kidney Epidemiology & Cost Center, University of Michigan , Ann Arbor, Michigan
- Division of Nephrology, Department of Medicine, University of Michigan , Ann Arbor, Michigan
| | - Brenda Gillespie
- Kidney Epidemiology & Cost Center, University of Michigan , Ann Arbor, Michigan
| | | | - Neil R Powe
- Division of General Internal Medicine, Department of Medicine, University of California , San Francisco, California
- Department of Medicine, Zuckerberg San Francisco General Hospital , San Francisco, California
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Goraya N, Simoni J, Sager LN, Madias NE, Wesson DE. Urine citrate excretion as a marker of acid retention in patients with chronic kidney disease without overt metabolic acidosis. Kidney Int 2019; 95:1190-1196. [PMID: 30846270 DOI: 10.1016/j.kint.2018.11.033] [Citation(s) in RCA: 61] [Impact Index Per Article: 12.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 11/17/2018] [Accepted: 11/21/2018] [Indexed: 11/30/2022]
Abstract
Acid (H+) retention appears to contribute to progressive decline in glomerular filtration rate (GFR) in patients with chronic kidney disease (CKD), including some patients without metabolic acidosis. Identification of patients with H+ retention but without metabolic acidosis could facilitate targeted alkali therapy; however, current methods to assess H+ retention are invasive and have little clinical utility. We tested the hypothesis that urine excretion of the pH-sensitive metabolite citrate can identify H+ retention in patients with reduced GFR but without overt metabolic acidosis. H+ retention was assessed based on the difference between observed and expected plasma total CO2 after an oral sodium bicarbonate load. The association between H+ retention and urine citrate excretion was evaluated in albuminuric CKD patients with eGFR 60-89 ml/min/1.73m2 (CKD 2, n=40) or >90 ml/min/1.73m2 (CKD 1, n = 26) before and after 30 days of base-producing fruits and vegetables. Baseline H+ retention was higher in CKD 2, while baseline urine citrate excretion was lower in CKD 2 compared to CKD 1. Base-producing fruits and vegetables decreased H+ retention in CKD 2 and increased urine citrate excretion in both groups. Thus, H+ retention is associated with lower urine citrate excretion, and reduction of H+ retention with a base-producing diet is associated with increased urine citrate excretion. These results support further exploration of the utility of urine citrate excretion to identify H+ retention in CKD patients with reduced eGFR but without metabolic acidosis, to determine their candidacy for kidney protection with dietary H+ reduction or alkali therapy.
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Affiliation(s)
- Nimrit Goraya
- Baylor Scott & White Health Department of Internal Medicine, Temple, Texas, USA; Texas A&M Health Sciences Center College of Medicine, Temple, Texas, USA
| | - Jan Simoni
- Texas Tech University Health Sciences Center Department of Surgery, Lubbock, Texas, USA
| | - Lauren N Sager
- Baylor Scott & White Health Department of Biostatistics, Temple, Texas, USA
| | - Nicolaos E Madias
- St. Elizabeth's Medical Center and Tufts University School of Medicine Department of Medicine, Boston, Massachusetts, USA
| | - Donald E Wesson
- Baylor Scott & White Health Department of Internal Medicine, Dallas, Texas, USA; Texas A&M Health Sciences Center College of Medicine, Dallas, Texas, USA.
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Djamali A, Singh T, Melamed ML, Stein JH, Aziz F, Parajuli S, Mohamed M, Garg N, Mandelbrot D, Wesson DE, Astor BC. Metabolic Acidosis 1 Year Following Kidney Transplantation and Subsequent Cardiovascular Events and Mortality: An Observational Cohort Study. Am J Kidney Dis 2019; 73:476-485. [PMID: 30704880 DOI: 10.1053/j.ajkd.2018.12.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2018] [Accepted: 12/02/2018] [Indexed: 12/24/2022]
Abstract
RATIONALE & OBJECTIVE Recent studies suggest that metabolic acidosis is associated with mortality and graft failure in kidney transplant recipients. However, it is unknown whether serum bicarbonate (measured as total carbon dioxide [tCO2] in serum) levels predict cardiovascular events (CVEs) following kidney transplantation. STUDY DESIGN Observational cohort study. SETTINGS & PARTICIPANTS Single-center study of 2,128 kidney transplant recipients free of CVEs during the first 13.5 months following transplantation. PREDICTOR tCO2 level at 1 year posttransplantation. OUTCOMES Ischemic, arrhythmic, and heart failure CVEs and death from any cause. ANALYTICAL APPROACH Independent associations were assessed using multivariable proportional hazards regression models. Restricted cubic spline Poisson models were used to explore nonlinear associations. Linear spline proportional hazards models were used to assess associations at different tCO2 levels. RESULTS The prevalence of metabolic acidosis defined as tCO2 level < 24 mEq/L was 38.8% (n=826). There were 384 recipients with a CVE and 610 deaths during a median follow-up of 4.0 years. CVEs included 241 ischemic, 137 arrhythmic, and 150 heart failure events. tCO2 level < 20 mEq/L was associated with increased risk for CVEs (adjusted HR [aHR], 2.00; 95% CI, 1.29-3.10) compared to the reference category of tCO2 level of 24.0 to 25.9 mEq/L. This association was primarily due to ischemic CVEs (aHR, 2.28; 95% CI, 1.34-3.90). For every 1 mEq/L lower tCO2 level for those with tCO2 < 24 mEq/L, risks for all CVEs and ischemic events were 17% and 15% higher, respectively (aHR for all CVEs of 0.83 [95% CI, 0.74-0.94] and aHR for ischemic CVEs of 0.85 [95% CI, 0.74-0.99]). Notably, tCO2 level < 20 mEq/L, compared to tCO2 level of 24.0 to 25.9 mEq/L, was independently associated with all-cause mortality (aHR, 1.43; 95% CI, 1.02-2.02). For every 1-mEq/L lower tCO2 level for those with tCO2 < 24 mEq/L, there was 17% higher risk for death (aHR, 0.83; 95% CI, 0.75-0.92). LIMITATIONS Single-center observational study. CONCLUSIONS Metabolic acidosis is an independent risk factor for ischemic CVEs after kidney transplantation. It is unknown whether correction of acidosis improves outcomes in these patients.
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Affiliation(s)
- Arjang Djamali
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI; Department of Surgery, University of Wisconsin School of Medicine and Public Health, Madison, WI.
| | - Tripti Singh
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Michal L Melamed
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY; Department of Epidemiology and Population Health, Albert Einstein College of Medicine, Bronx, NY
| | - James H Stein
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Fahad Aziz
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Sandesh Parajuli
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Maha Mohamed
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Neetika Garg
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Didier Mandelbrot
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI
| | - Donald E Wesson
- Baylor Scott and White Health and Wellness Center of BSW Health, Dallas, TX
| | - Brad C Astor
- Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI; Department of Population Health Sciences, University of Wisconsin School of Medicine and Public Health, Madison, WI
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Kendrick J, Shah P, Andrews E, You Z, Nowak K, Pasch A, Chonchol M. Effect of Treatment of Metabolic Acidosis on Vascular Endothelial Function in Patients with CKD: A Pilot Randomized Cross-Over Study. Clin J Am Soc Nephrol 2018; 13:1463-1470. [PMID: 30237219 PMCID: PMC6218835 DOI: 10.2215/cjn.00380118] [Citation(s) in RCA: 44] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2018] [Accepted: 08/08/2018] [Indexed: 01/01/2023]
Abstract
BACKGROUND AND OBJECTIVES We examined the effect of alkali replacement for metabolic acidosis on vascular endothelial function in patients with CKD. METHODS We performed a pilot, prospective, open-label 14-week crossover study examining the effect of oral sodium bicarbonate treatment on vascular function in 20 patients with an eGFR of 15-44 ml/min per 1.73 m2 with low serum bicarbonate levels (16-21 mEq/L). Each period was 6 weeks in duration with a 2-week washout period in between. Patients were treated to goal serum bicarbonate of ≥23 mEq/L. The primary end point was change in brachial artery flow-mediated dilation (FMD) between treatment and control conditions. Secondary end points included changes in markers of inflammation, bone turnover, mineral metabolism, and calcification. RESULTS Eighteen patients completed the study and were included in the primary efficacy analysis. The mean (SD) age and eGFR were 59 (12) years and 26 (8) ml/min per 1.73 m2, respectively. Serum bicarbonate increased significantly with sodium bicarbonate treatment (+2.7±2.9 mEq/L, P≤0.001), whereas there was no change in bicarbonate levels in the control group. FMD significantly improved after sodium bicarbonate therapy (mean±SD, FMD baseline: 4.1%±4.1%; 6 weeks: 5.2%±2.9%; P=0.04) There was no significant change in FMD in the control group (mean±SD, FMD baseline: 4.6%±3.1%; 6 weeks: 4.1%±3.4%; P=0.20). Compared with control, sodium bicarbonate treatment resulted in a significant increase in FMD (mean, 1.8%; 95% confidence interval, 0.3 to 3.3; P=0.02). There was no significant change in bone markers or serum calcification propensity with treatment. Serum phosphorus and intact fibroblast growth factor 23 increased significantly during treatment. CONCLUSIONS Treatment of metabolic acidosis with sodium bicarbonate significantly improved vascular endothelial function in patients with stages 3b and 4 CKD.
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Affiliation(s)
- Jessica Kendrick
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado; and
| | - Pratik Shah
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado; and
| | - Emily Andrews
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado; and
| | - Zhiying You
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado; and
| | - Kristen Nowak
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado; and
| | - Andreas Pasch
- Department of Biomedical Research, University of Bern and Calciscon, Bern, Switzerland
| | - Michel Chonchol
- Division of Renal Diseases and Hypertension, University of Colorado Denver, Aurora, Colorado; and
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Wiegand A, Ritter A, Graf N, Arampatzis S, Sidler D, Hadaya K, Müller TF, Wagner CA, Wüthrich RP, Mohebbi N. Preservation of kidney function in kidney transplant recipients by alkali therapy (Preserve-Transplant Study): rationale and study protocol. BMC Nephrol 2018; 19:177. [PMID: 30001705 PMCID: PMC6043955 DOI: 10.1186/s12882-018-0956-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Accepted: 06/24/2018] [Indexed: 01/01/2023] Open
Abstract
Background Graft survival after kidney transplantation has significantly improved within the last decades but there is a substantial number of patients with declining transplant function and graft loss. Over the past years several studies have shown that metabolic acidosis plays an important role in the progression of Chronic Kidney Disease (CKD) and that alkalinizing therapies significantly delayed progression of CKD. Importantly, metabolic acidosis is highly prevalent in renal transplant patients and a recent retrospective study has shown that metabolic acidosis is associated with increased risk of graft loss and patient death in kidney transplant recipients. However, no prospective trial has been initiated yet to test the role of alkali treatment on renal allograft function. Methods The Preserve-Transplant Study is an investigator-initiated, prospective, patient-blinded, multi-center, randomized, controlled phase-IV trial with two parallel-groups comparing sodium bicarbonate to placebo. The primary objective is to test if alkali treatment will preserve kidney graft function and diminish the progression of CKD in renal transplant patients by assesing the change in eGFR over 2 years from baseline. Additionally we want to investigate the underlying pathomechanisms of nephrotoxicity of metabolic acidosis. Discussion This study has the potential to provide evidence that alkali treatment may slow or reduce the progression towards graft failure and significantly decrease the rate of end stage renal disease (ESRD), thus prolonging long-term graft survival. The implementation of alkali therapy into the drug regimen of kidney transplant recipients would have a favorable risk-benefit ratio since alkali supplements are routinely used in CKD patients and represent a well-tolerated, safe and cost-effective treatment. Trial registration ClinicalTrials.gov NCT03102996. Trial registration was completed on April 6, 2017.
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Affiliation(s)
- Anna Wiegand
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Alexander Ritter
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Nicole Graf
- Graf Biostatistics, Wintherthur, Switzerland
| | - Spyridon Arampatzis
- Department of Nephrology and Hypertension, University Hospital Berne, Berne, Switzerland
| | - Daniel Sidler
- Department of Nephrology and Hypertension, University Hospital Berne, Berne, Switzerland
| | - Karine Hadaya
- Division of Nephrology, University Hospital Geneva, Geneva, Switzerland
| | - Thomas F Müller
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
| | - Rudolf P Wüthrich
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Nilufar Mohebbi
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland.
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Goraya N, Wesson DE. Kidney Response to the Spectrum of Diet-Induced Acid Stress. Nutrients 2018; 10:nu10050596. [PMID: 29751620 PMCID: PMC5986476 DOI: 10.3390/nu10050596] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 05/01/2018] [Accepted: 05/08/2018] [Indexed: 12/16/2022] Open
Abstract
Chronic ingestion of the acid (H+)-producing diets that are typical of developed societies appears to pose a long-term threat to kidney health. Mechanisms employed by kidneys to excrete this high dietary H+ load appear to cause long-term kidney injury when deployed over many years. In addition, cumulative urine H+ excretion is less than the cumulative increment in dietary H+, consistent with H+ retention. This H+ retention associated with the described high dietary H+ worsens as the glomerular filtration rate (GFR) declines which further exacerbates kidney injury. Modest H+ retention does not measurably change plasma acid–base parameters but, nevertheless, causes kidney injury and might contribute to progressive nephropathy. Current clinical methods do not detect H+ retention in its early stages but the condition manifests as metabolic acidosis as it worsens, with progressive decline of the glomerular filtration rate. We discuss this spectrum of H+ injury, which we characterize as “H+ stress”, and the emerging evidence that high dietary H+ constitutes a threat to long-term kidney health.
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Affiliation(s)
- Nimrit Goraya
- Baylor Scott & White Health Department of Internal Medicine, Temple, TX 76508, USA.
- A&M Health Science Center College of Medicine, Temple, TX 76508, USA.
| | - Donald E Wesson
- Baylor Scott & White Health Department of Internal Medicine, Dallas, TX 75210, USA.
- A&M Health Science Center College of Medicine, Dallas, TX 75210, USA.
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Crews DC, Banerjee T, Wesson DE, Morgenstern H, Saran R, Burrows NR, Williams DE, Powe NR. Race/Ethnicity, Dietary Acid Load, and Risk of End-Stage Renal Disease among US Adults with Chronic Kidney Disease. Am J Nephrol 2018; 47:174-181. [PMID: 29525790 PMCID: PMC5906156 DOI: 10.1159/000487715] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2017] [Accepted: 01/11/2018] [Indexed: 12/21/2022]
Abstract
BACKGROUND Dietary acid load (DAL) contributes to the risk of CKD and CKD progression. We sought to determine the relation of DAL to racial/ethnic differences in the risk of end-stage renal disease (ESRD) among persons with CKD. METHODS Among 1,123 non-Hispanic black (NHB) and non-Hispanic white (NHW) National Health and Nutrition Examination Survey III participants with estimated glomerular filtration rate 15-59 mL/min/1.73 m2, DAL was estimated using the Remer and Manz net acid excretion (NAEes) formula and 24-h dietary recall. ESRD events were ascertained via linkage with Medicare. A competing risk model (accounting for death) was used to estimate the hazard ratio (HR) for treated ESRD, comparing NHBs with NHWs, adjusting for demographic, clinical and nutritional factors (body surface area, total caloric intake, serum bicarbonate, protein intake), and NAEes. Additionally, whether the relation of NAEes with ESRD risk varied by race/ethnicity was tested. RESULTS At baseline, NHBs had greater NAEes (50.9 vs. 44.2 mEq/day) than NHWs. It was found that 22% developed ESRD over a median of 7.5 years. The unadjusted HR comparing NHBs to NHWs was 3.35 (95% CI 2.51-4.48) and adjusted HR (for factors above) was 1.68 (95% CI 1.18-2.38). A stronger association of NAE with risk of ESRD was observed among NHBs (adjusted HR per mEq/day increase in NAE 1.21, 95% CI 1.12-1.31) than that among NHWs (HR 1.08, 95% CI 0.96-1.20), p interaction for race/ethnicity × NAEes = 0.004. CONCLUSIONS Among US adults with CKD, the association of DAL with progression to ESRD is stronger among NHBs than NHWs. DAL is worthy of further investigation for its contribution to kidney outcomes across race/ethnic groups.
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Affiliation(s)
- Deidra C Crews
- Division of Nephrology, Department of Medicine, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Welch Center for Prevention, Epidemiology and Clinical Research, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
- Johns Hopkins Center for Health Equity, Johns Hopkins Medical Institutions, Baltimore, Maryland, USA
| | - Tanushree Banerjee
- Division of General Internal Medicine, Department of Medicine, University of California, San Francisco, California, USA
| | - Donald E Wesson
- Diabetes Health and Wellness Institute, Baylor Scott and White Health, Dallas, Texas, USA
| | - Hal Morgenstern
- Departments of Epidemiology and Environmental Health Sciences, School of Public Health, and Department of Urology, Medical School, University of Michigan, Ann Arbor, Michigan, USA
| | - Rajiv Saran
- Kidney Epidemiology and Cost Center, University of Michigan, Ann Arbor, Michigan, USA
- Division of Nephrology, Department of Medicine, University of Michigan, Ann Arbor, Michigan, USA
| | - Nilka Ríos Burrows
- Division of Diabetes Translation, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Desmond E Williams
- Center for Global Health, Centers for Disease Control and Prevention, Atlanta, Georgia, USA
| | - Neil R Powe
- Division of General Internal Medicine, Department of Medicine, University of California, San Francisco, California, USA
- Department of Medicine, San Francisco General Hospital, San Francisco, California, USA
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Raphael KL, Gilligan S, Hostetter TH, Greene T, Beddhu S. Association between Urine Ammonium and Urine TGF- β1 in CKD. Clin J Am Soc Nephrol 2018; 13:223-230. [PMID: 29146699 PMCID: PMC5967432 DOI: 10.2215/cjn.07510717] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2017] [Accepted: 10/16/2017] [Indexed: 11/23/2022]
Abstract
BACKGROUND AND OBJECTIVES Urinary ammonium excretion increases in response to nonvolatile acids to maintain normal systemic bicarbonate and pH. However, enhanced ammonia production promotes tubulointerstitial fibrosis in animal models. Therefore, a subset of individuals with CKD and normal bicarbonate may have acid-mediated kidney fibrosis that might be better linked with ammonium excretion than bicarbonate. We hypothesized that urine TGF-β1, as an indicator of kidney fibrosis, would be more tightly linked with urine ammonium excretion than serum bicarbonate and other acid-base indicators. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: We measured serum bicarbonate and urinary ammonium, titratable acids, pH, and TGF-β1/creatinine in 144 persons with CKD. Multivariable-adjusted linear regression models determined the cross-sectional association between TGF-β1/creatinine and serum bicarbonate, urine ammonium excretion, urine titratable acids excretion, and urine pH. RESULTS Mean eGFR was 42 ml/min per 1.73 m2, mean age was 65 years old, 78% were men, and 62% had diabetes. Mean urinary TGF-β1/creatinine was 102 (49) ng/g, mean ammonium excretion was 1.27 (0.72) mEq/h, mean titratable acids excretion was 1.14 (0.65) mEq/h, mean urine pH was 5.6 (0.5), and mean serum bicarbonate was 23 (3) mEq/L. After adjusting for eGFR, proteinuria, and other potential confounders, each SD increase of urine ammonium and urine pH was associated with a statistically significant 1.22-fold (95% confidence interval, 1.11 to 1.35) or 1.11-fold (95% confidence interval, 1.02 to 1.21) higher geometric mean urine TGF-β1/creatinine, respectively. Each SD increase of serum bicarbonate and urine titratable acids was associated with a nonsignificant 1.06-fold (95% confidence interval, 0.97 to 1.16) or 1.03-fold (95% confidence interval, 0.92 to 1.14) higher geometric mean urine TGF-β1/creatinine, respectively. CONCLUSIONS Urinary ammonium excretion but not serum bicarbonate is associated with higher urine TGF-β1/creatinine.
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Affiliation(s)
- Kalani L. Raphael
- Department of Internal Medicine, University of Utah Health, Salt Lake City, Utah
- Medicine Section and Research Section, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah; and
| | - Sarah Gilligan
- Department of Internal Medicine, University of Utah Health, Salt Lake City, Utah
| | - Thomas H. Hostetter
- Department of Internal Medicine, Case Western Reserve School of Medicine, Cleveland, Ohio
| | - Tom Greene
- Department of Internal Medicine, University of Utah Health, Salt Lake City, Utah
| | - Srinivasan Beddhu
- Department of Internal Medicine, University of Utah Health, Salt Lake City, Utah
- Medicine Section and Research Section, Veterans Affairs Salt Lake City Health Care System, Salt Lake City, Utah; and
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Goraya N, Simoni J, Sager LN, Pruszynski J, Wesson DE. Acid retention in chronic kidney disease is inversely related to GFR. Am J Physiol Renal Physiol 2018; 314:F985-F991. [PMID: 29357423 DOI: 10.1152/ajprenal.00463.2017] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Greater H+ retention in animal models of chronic kidney disease (CKD) mediates faster glomerular filtration rate (GFR) decline and dietary H+ reduction slows eGFR decline in CKD patients with reduced eGFR and H+ retention due to the high acid (H+) diets of developed societies. We examined if H+ retention in CKD is inversely associated with estimated GFR (eGFR) using cross-sectional and longitudinal analysis of individuals with CKD stage 1 (>90 ml·min- 1·1.73 m-2), CKD stage 2 (60-89 ml/min per 1.73 m2), and CKD stage 3 (30-59 ml·min- 1·1.73 m-2) eGFR. H+ retention was assessed using the difference between observed and expected plasma total CO2 2 h after 0.5 meq/kg body wt oral NaHCO3. H+ retention was higher in CKD 2 vs. CKD 1 ( P < 0.01) and in CKD 3 vs. CKD 2 ( P < 0.02) at baseline and 5 yr, and was higher in CKD 2 vs. CKD 1 ( P < 0.01) at 10 yr. All groups had lower eGFR at subsequent time points ( P < 0.01) but H+ retention was not different among the three time points for CKD 1. By contrast, eGFR decrease was associated with higher H+ retention in CKD 2 at 5 yr ( P = 0.04) and 10 yr ( P < 0.01) and with higher H+ retention in CKD 3 at 5 yr ( P < 0.01). Yearly eGFR decline rate was faster in CKD 2 vs. CKD 1 ( P < 0.01) and in CKD 3 vs. CKD 2 ( P < 0.01). The data show that H+ retention is inversely associated with eGFR, with faster eGFR decline, and support the need for greater dietary H+ reduction therapy for CKD individuals with lower eGFR.
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Affiliation(s)
- Nimrit Goraya
- Department of Internal Medicine, Texas A&M College of Medicine, Temple, Texas.,Department of Internal Medicine, Baylor Scott & White Health, Temple, Texas
| | - Jan Simoni
- Department of Surgery, Texas Tech University Health Sciences Center , Lubbock, Texas
| | - Lauren N Sager
- Department of Biostatistics, Baylor Scott & White Health, Temple, Texas
| | - Jessica Pruszynski
- Department of Cardiovascular and Thoracic Surgery, University of Texas Southwestern , Dallas, Texas
| | - Donald E Wesson
- Department of Internal Medicine, Texas A&M Health Sciences Center College of Medicine , Dallas, Texas.,Baylor Scott & White Health and Wellness Center, Dallas, Texas
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Abstract
Metabolic acidosis is not uncommon in CKD and is linked with bone demineralization, muscle catabolism, and higher risks of CKD progression and mortality. Clinical practice guidelines recommend maintaining serum total CO2 at ≥22 mEq/L to help prevent these complications. Although a definitive trial testing whether correcting metabolic acidosis improves clinical outcomes has not been conducted, results from small, single-center studies support this notion. Furthermore, biologic plausibility supports the notion that a subset of patients with CKD have acid-mediated organ injury despite having a normal serum total CO2 and might benefit from oral alkali before overt acidosis develops. Identifying these individuals with subclinical metabolic acidosis is challenging, but recent results suggest that urinary acid excretion measurements may be helpful. The dose of alkali to provide in this setting is unknown as well. The review discusses these topics and the prevalence and risk factors of metabolic acidosis, mechanisms of acid-mediated organ injury, results from interventional studies, and potential harms of alkali therapy in CKD.
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Affiliation(s)
- Kalani L Raphael
- Veterans Affairs Salt Lake City Health Care System and Division of Nephrology and Hypertension, Department of Internal Medicine, University of Utah, Salt Lake City, Utah
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46
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Nagami GT, Hamm LL. Regulation of Acid-Base Balance in Chronic Kidney Disease. Adv Chronic Kidney Dis 2017; 24:274-279. [PMID: 29031353 DOI: 10.1053/j.ackd.2017.07.004] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/03/2017] [Accepted: 07/28/2017] [Indexed: 11/11/2022]
Abstract
The kidneys play a major role in the regulation of acid-base balance by reabsorbing bicarbonate filtered by the glomeruli and excreting titratable acids and ammonia into the urine. In CKD, with declining kidney function, acid retention and metabolic acidosis occur, but the extent of acid retention depends not only on the degree of kidney impairment but also on the dietary acid load. Acid retention can occur even when the serum bicarbonate level is apparently normal. With reduced kidney function, acid transport processes in the surviving nephrons are augmented but as disease progresses ammonia excretion and, in some individuals, the ability to reabsorb bicarbonate falls, whereas titratable acid excretion is preserved until kidney function is severely impaired. Urinary ammonia levels are used to gauge the renal response to acid loads and are best assessed by direct measurement of urinary ammonia levels rather than by indirect assessments. In individuals with acidosis from CKD, an inappropriately low degree of ammonia excretion points to the pathogenic role of impaired urinary acid excretion. The presence of a normal bicarbonate level in CKD complicates the interpretation of the urinary ammonia excretion as such individuals could be in acid-base balance or could be retaining acid without manifesting a low bicarbonate level. At this time, the decision to give bicarbonate supplementation in CKD is reserved for those with a bicarbonate level of 22 mEq/L, but because of potential harm of overtreatment, supplementation should be adjusted to maintain a bicarbonate level of <26 mEq/L.
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Goraya N, Wesson DE. Management of the Metabolic Acidosis of Chronic Kidney Disease. Adv Chronic Kidney Dis 2017; 24:298-304. [PMID: 29031356 DOI: 10.1053/j.ackd.2017.06.006] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 06/27/2017] [Indexed: 01/31/2023]
Abstract
Subjects with CKD and reduced glomerular filtration rate are at risk for chronic metabolic acidosis, and CKD is its most common cause. Untreated metabolic acidosis, even in its mildest forms, is associated with increased mortality and morbidity and should therefore be treated. If reduced glomerular filtration rate or the tubule abnormality causing chronic metabolic acidosis cannot be corrected, it is typically treated with dietary acid (H+) reduction using Na+-based alkali, usually NaHCO3. Dietary H+ reduction can also be accomplished with the addition of base-producing foods such as fruits and vegetables and limiting intake of H+-producing foods like animal-sourced protein. The optimal dose of Na+-based alkali that prevents the untoward effects of metabolic acidosis while minimizing adverse effects and the appropriate combination of this traditional therapy with dietary strategies remain to be determined by ongoing studies. Recent emerging evidence supports a phenomenon of H+ retention, which precedes the development of metabolic acidosis by plasma acid-base parameters, but further studies will be needed to determine how best to identify patients with this phenomenon and whether they too should be treated with dietary H+ reduction.
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Izumi Y, Inoue H, Nakayama Y, Eguchi K, Yasuoka Y, Matsuo N, Nonoguchi H, Kakizoe Y, Kuwabara T, Mukoyama M. TSS-Seq analysis of low pH-induced gene expression in intercalated cells in the renal collecting duct. PLoS One 2017; 12:e0184185. [PMID: 28859164 PMCID: PMC5578634 DOI: 10.1371/journal.pone.0184185] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Accepted: 08/18/2017] [Indexed: 12/24/2022] Open
Abstract
Metabolic acidosis often results from chronic kidney disease; in turn, metabolic acidosis accelerates the progression of kidney injury. The mechanisms for how acidosis facilitates kidney injury are not fully understood. To investigate whether low pH directly affects the expression of genes controlling local homeostasis in renal tubules, we performed transcription start site sequencing (TSS-Seq) using IN-IC cells, a cell line derived from rat renal collecting duct intercalated cells, with acid loading for 24 h. Peak calling identified 651 up-regulated and 128 down-regulated TSSs at pH 7.0 compared with those at pH 7.4. Among them, 424 and 38 TSSs were ≥ 1.0 and ≤ -1.0 in Log2 fold change, which were annotated to 193 up-regulated and 34 down-regulated genes, respectively. We used gene ontology analysis and manual curation to profile the up-regulated genes. The analysis revealed that many up-regulated genes are involved in renal fibrosis, implying potential molecular mechanisms induced by metabolic acidosis. To verify the activity of the ubiquitin-proteasome system (UPS), a candidate pathway activated by acidosis, we examined the expression of proteins from cells treated with a proteasome inhibitor, MG132. The expression of ubiquitinated proteins was greater at pH 7.0 than at pH 7.4, suggesting that low pH activates the UPS. The in vivo study demonstrated that acid loading increased the expression of ubiquitin proteins in the collecting duct cells in mouse kidneys. Motif analysis revealed Egr1, the mRNA expression of which was increased at low pH, as a candidate factor that possibly stimulates gene expression in response to low pH. In conclusion, metabolic acidosis can facilitate renal injury and fibrosis during kidney disease by locally activating various pathways in the renal tubules.
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Affiliation(s)
- Yuichiro Izumi
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Hideki Inoue
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Yushi Nakayama
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
- * E-mail:
| | - Koji Eguchi
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Yukiko Yasuoka
- Department of Physiology, Kitasato University School of Medicine, Sagamihara, Japan
| | - Naomi Matsuo
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Hiroshi Nonoguchi
- Department of Internal Medicine and Education & Research Center, Kitasato University Medical Center, Kitamoto, Japan
| | - Yutaka Kakizoe
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Takashige Kuwabara
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
| | - Masashi Mukoyama
- Department of Nephrology, Kumamoto University Graduate School of Medical Sciences, Kumamoto, Japan
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Hanafusa N, Lodebo BT, Kopple JD. Current Uses of Dietary Therapy for Patients with Far-Advanced CKD. Clin J Am Soc Nephrol 2017; 12:1190-1195. [PMID: 28228464 PMCID: PMC5498353 DOI: 10.2215/cjn.09340916] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
For several decades, inquiry concerning dietary therapy for nondialyzed patients with CKD has focused mainly on its capability to retard progression of CKD. However, several studies published in recent years indicate that, independent of whether diet can delay progression of CKD, well designed low-protein diets may provide a number of benefits for people with advanced CKD who are close to requiring or actually in need of RRT. Dietary therapy may both maintain good nutritional status and safely delay the need for chronic dialysis in such patients, offering the possibility of improving quality of life and reducing health care costs. With the growing interest in incremental dialysis, dietary therapy may enable lower doses of dialysis to be safely and effectively used, even as GFR continues to decrease. Such combinations of dietary and incremental dialysis therapy might slow the rate of loss of residual GFR, possibly reduce mortality in patients with advanced CKD, improve quality of life, and also, reduce health care costs. The amount of evidence that supports these possibilities is limited, and more well designed, randomized clinical trials are clearly indicated.
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Affiliation(s)
- Norio Hanafusa
- Department of Blood Purification, Kidney Center, Tokyo Women’s Medical University, Tokyo, Japan
- Division of Nephrology and Hypertension, Los Angeles Biomedical Research Institute at Harbor–UCLA Medical Center, Torrance, California
| | - Bereket Tessema Lodebo
- Division of Nephrology and Hypertension, Los Angeles Biomedical Research Institute at Harbor–UCLA Medical Center, Torrance, California
- Department of Public Health Sciences, Karolinska Institutet, Stockholm, Sweden
| | - Joel D. Kopple
- Division of Nephrology and Hypertension, Los Angeles Biomedical Research Institute at Harbor–UCLA Medical Center, Torrance, California
- Department of Medicine, David Geffen School of Medicine at UCLA, Los Angeles, California; and
- UCLA Fielding School of Public Health, Los Angeles, California
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Abstract
PURPOSE OF REVIEW Acid-base homeostasis is impaired in chronic kidney disease (CKD) and may contribute to disease progression. Diabetes, a major cause of CKD worldwide, may exacerbate acidosis further due to differences in acid production and excretion. Here, we review the role of abnormal acid-base homeostasis in the pathogenesis and progression of diabetes and diabetic kidney disease. RECENT FINDINGS Acidosis and dietary acid loading may contribute to the development and worsening of insulin resistance and hypertension, thereby promoting diabetes and diabetic CKD. However, although metabolic acidosis associates with progression of CKD generally, the results in diabetic CKD are mixed. Data suggests that metabolic acid production in diabetes may be higher than would be predicted based on dietary intake alone, and new observational data suggests that this higher diet-independent acid production could potentially be protective. The role of acid-base homeostasis in diabetic CKD progression is complex and must consider differences in endogenous acid production and excretion in diabetes. Ongoing observational and interventional studies in this field should consider the unique physiology of diabetes.
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Affiliation(s)
- Pascale Khairallah
- Department of Medicine, Duke University School of Medicine, Durham, NC, USA
| | - Julia J Scialla
- Duke Clinical Research Institute, Duke University School of Medicine, Durham, NC, USA.
- Department of Medicine, Durham Veterans Affairs Medical Center, Durham, NC, USA.
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