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Prytula A, Shroff R, van Gremberghe I, Krupka K, Bacchetta J, Benetti E, Grenda R, Guzzo I, Kanzelmeyer N, Büyükkaragöz B, Kranz B, Nalçacıoğlu H, Oh J, Pape L, Shenoy M, Sellier-Leclerc AL, Tönshoff B. Metabolic Acidosis Is Associated With an Accelerated Decline of Allograft Function in Pediatric Kidney Transplantation. Kidney Int Rep 2024; 9:1684-1693. [PMID: 38899185 PMCID: PMC11184248 DOI: 10.1016/j.ekir.2024.04.007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2024] [Revised: 03/26/2024] [Accepted: 04/01/2024] [Indexed: 06/21/2024] Open
Abstract
Introduction We investigated the relationship between metabolic acidosis over time and allograft outcome in pediatric kidney transplantation (KTx). Methods This registry study collected data up to 10 years posttransplant. Survival analysis for a composite end point of graft loss or estimated glomerular filtration rate (eGFR) ≤ 30 ml/min per 1.73 m2 or ≥50% decline from eGFR at month 3 posttransplant was performed. The association of serum bicarbonate concentration (HCO3 -) < 22 mmol/l (metabolic acidosis) and HCO3 - < 18 mmol/l (severe metabolic acidosis) with allograft outcome was investigated using stratified Cox models and marginal structural models. Secondary analyses included the identification of risk factors for metabolic acidosis and the relationship between alkali supplementation and allograft outcome. Results We report on 1911 patients, of whom 347 reached the composite end point. The prevalence of metabolic acidosis over time ranged from 20.4% to 38.9%. In the adjusted Cox models, metabolic acidosis (hazard ratio [HR], 2.00; 95% confidence interval [CI], 1.54-2.60) and severe metabolic acidosis (HR, 2.49; 95% CI, 1.56-3.99) were associated with allograft dysfunction. Marginal structural models showed similar results (HR, 1.75; 95% CI, 1.32-2.31 and HR, 2.09; 95% CI, 1.23-3.55, respectively). Older age was associated with a lower risk of metabolic acidosis (odds ratio [OR] 0.93/yr older; 95% CI, 0.91-0.96) and severe metabolic acidosis (OR, 0.89; 95% CI, 0.84-0.95). Patients with uncontrolled metabolic acidosis had the worst outcome compared to those without metabolic acidosis and without alkali (HR, 3.70; 95% CI, 2.54-5.40). Conclusion The degree of metabolic acidosis is associated with allograft dysfunction.
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Affiliation(s)
- Agnieszka Prytula
- Department of Pediatric Nephrology and Rheumatology, Ghent University Hospital, Belgium
| | | | - Ineke van Gremberghe
- Biostatistics Unit, Faculty of Medicine and Health Sciences, Ghent University, Belgium
| | - Kai Krupka
- Department of Pediatrics I, University Children’s Hospital Heidelberg, Germany
| | - Justine Bacchetta
- Department of Pediatric Nephrology and Rheumatology, CHU de Lyon, Bron, France
| | - Elisa Benetti
- Pediatric Nephrology, Dialysis and Transplant Unit, Laboratory of Immunopathology and Molecular Biology of the Kidney, Department of Women’s and Children’s Health, Padua University Hospital, Padua, Italy
| | - Ryszard Grenda
- Department of Nephrology, Kidney Transplantation and Arterial Hypertension, Children’s Memorial Health Institute, Warsaw, Poland
| | - Isabella Guzzo
- Division of Nephrology, Dialysis and Renal Transplant Unit, Bambino Gesù Children’s Hospital IRCCS, Rome, Italy
| | - Nele Kanzelmeyer
- Department of Pediatric Kidney, Liver and Metabolic Diseases, Hannover Medical School, Hannover, Germany
| | | | - Birgitta Kranz
- Pediatric Nephrology, University Children‘s Hospital, Münster, Germany
| | - Hülya Nalçacıoğlu
- Pediatric Nephrology Department, Ondokuz Mayis University, Samsun, Turkey
| | - Jun Oh
- Department of Pediatric Nephrology and Transplantation, University Children’s Hospital, University Medical Center Hamburg/Eppendorf, Hamburg, Germany
| | - Lars Pape
- Department of Pediatrics II, University Hospital of Essen, Essen, Germany
| | - Mohan Shenoy
- Royal Manchester Children’s Hospital, Manchester, UK
| | | | - Burkhard Tönshoff
- Department of Pediatrics I, University Children’s Hospital Heidelberg, Germany
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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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Kilduff S, Hayde N, Viswanathan S, Reidy K, Abramowitz MK. Metabolic acidosis in pediatric kidney transplant recipients. Pediatr Nephrol 2023; 38:4165-4173. [PMID: 37422606 DOI: 10.1007/s00467-023-06072-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 06/22/2023] [Accepted: 06/22/2023] [Indexed: 07/10/2023]
Abstract
BACKGROUND Metabolic acidosis is a risk factor for faster kidney function decline in chronic kidney disease (CKD) and in adult kidney transplant recipients (KTRs). We hypothesized that metabolic acidosis would be highly prevalent and associated with worse allograft function in pediatric KTRs. METHODS Pediatric KTRs at Montefiore Medical Center from 2010 to 2018 were included. Metabolic acidosis was defined as serum bicarbonate < 22 mEq/L or receiving alkali therapy. Regression models were adjusted for demographic factors and donor/recipient characteristics. RESULTS Sixty-three patients were identified with a median age at transplant of 10.5 (interquartile range (IQR) 4.4-15.2) years and post-transplant follow-up of 3 (IQR 1-5) years. Baseline serum bicarbonate was 21.7 ± 2.4 mEq/L, serum bicarbonate < 22 mEq/L was present in 28 (44%), and 44% of all patients were receiving alkali therapy. The prevalence of acidosis ranged from 58 to 70% during the first year of follow-up. At baseline, each 1-year higher age at transplant and every 10 ml/min/1.73 m2 higher eGFR were associated with 0.16 mEq/L (95% CI: 0.03-0.3) and 0.24 mEq/L (95% CI: 0.01-0.5) higher serum bicarbonate, respectively. Older age at transplant was associated with lower odds of acidosis (OR: 0.84; 95% CI: 0.72-0.97). During follow-up, metabolic acidosis was independently associated with 8.2 ml/min/1.73 m2 (95% CI 4.4-12) lower eGFR compared to not having acidosis; furthermore, eGFR was significantly lower among KTRs with unresolved acidosis compared with resolved acidosis. CONCLUSIONS Among pediatric KTRs, metabolic acidosis was highly prevalent in the first year post-transplantation and was associated with lower eGFR during follow-up. A higher resolution version of the Graphical abstract is available as Supplementary information.
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Affiliation(s)
- Stella Kilduff
- The Children's Hospital at Montefiore/Einstein, Bronx, NY, USA.
- Albert Einstein College of Medicine, Bronx, NY, USA.
| | - Nicole Hayde
- The Children's Hospital at Montefiore/Einstein, Bronx, NY, USA
| | | | - Kimberly Reidy
- The Children's Hospital at Montefiore/Einstein, Bronx, NY, USA
| | - Matthew K Abramowitz
- Department of Medicine, Albert Einstein College of Medicine, Bronx, NY, USA
- Institute for Aging Research, Albert Einstein College of Medicine, Bronx, NY, USA
- Diabetes Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
- Fleischer Institute for Diabetes and Metabolism, Albert Einstein College of Medicine, Bronx, NY, USA
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Mohebbi N, Ritter A, Wiegand A, Graf N, Dahdal S, Sidler D, Arampatzis S, Hadaya K, Mueller TF, Wagner CA, Wüthrich RP. Sodium bicarbonate for kidney transplant recipients with metabolic acidosis in Switzerland: a multicentre, randomised, single-blind, placebo-controlled, phase 3 trial. Lancet 2023; 401:557-567. [PMID: 36708734 DOI: 10.1016/s0140-6736(22)02606-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/06/2022] [Revised: 11/17/2022] [Accepted: 12/13/2022] [Indexed: 01/27/2023]
Abstract
BACKGROUND Metabolic acidosis is common in kidney transplant recipients and is associated with declining graft function. Sodium bicarbonate treatment effectively corrects metabolic acidosis, but no prospective studies have examined its effect on graft function. Therefore, we aimed to test whether sodium bicarbonate treatment would preserve graft function and slow the progression of estimated glomerular filtration rate (GFR) decline in kidney transplant recipients. METHODS The Preserve-Transplant Study was a multicentre, randomised, single-blind, placebo-controlled, phase 3 trial at three University Hospitals in Switzerland (Zurich, Bern, and Geneva), which recruited adult (aged ≥18 years) male and female long-term kidney transplant recipients if they had undergone transplantation more than 1 year ago. Key inclusion criteria were an estimated GFR between 15 mL/min per 1·73 m2 and 89 mL/min per 1·73 m2, stable allograft function in the last 6 months before study inclusion (<15% change in serum creatinine), and a serum bicarbonate of 22 mmol/L or less. We randomly assigned patients (1:1) to either oral sodium bicarbonate 1·5-4·5 g per day or matching placebo using web-based data management software. Randomisation was stratified by study centre and gender using a permuted block design to guarantee balanced allocation. We did multi-block randomisation with variable block sizes of two and four. Treatment duration was 2 years. Acid-resistant soft gelatine capsules of 500 mg sodium bicarbonate or matching 500 mg placebo capsules were given at an initial dose of 500 mg (if bodyweight was <70 kg) or 1000 mg (if bodyweight was ≥70 kg) three times daily. The primary endpoint was the estimated GFR slope over the 24-month treatment phase. The primary efficacy analyses were applied to a modified intention-to-treat population that comprised all randomly assigned participants who had a baseline visit. The safety population comprised all participants who received at least one dose of study drug. The trial is registered with ClinicalTrials.gov, NCT03102996. FINDINGS Between June 12, 2017, and July 10, 2019, 1114 kidney transplant recipients with metabolic acidosis were assessed for trial eligibility. 872 patients were excluded and 242 were randomly assigned to the study groups (122 [50%] to the placebo group and 120 [50%] to the sodium bicarbonate group). After secondary exclusion of two patients, 240 patients were included in the intention-to-treat analysis. The calculated yearly estimated GFR slopes over the 2-year treatment period were a median -0·722 mL/min per 1·73 m2 (IQR -4·081 to 1·440) and mean -1·862 mL/min per 1·73 m2 (SD 6·344) per year in the placebo group versus median -1·413 mL/min per 1·73 m2 (IQR -4·503 to 1·139) and mean -1·830 mL/min per 1·73 m2 (SD 6·233) per year in the sodium bicarbonate group (Wilcoxon rank sum test p=0·51; Welch t-test p=0·97). The mean difference was 0·032 mL/min per 1·73 m2 per year (95% CI -1·644 to 1·707). There were no significant differences in estimated GFR slopes in a subgroup analysis and a sensitivity analysis confirmed the primary analysis. Although the estimated GFR slope did not show a significant difference between the treatment groups, treatment with sodium bicarbonate effectively corrected metabolic acidosis by increasing serum bicarbonate from 21·3 mmol/L (SD 2·6) to 23·0 mmol/L (2·7) and blood pH from 7·37 (SD 0·06) to 7·39 (0·04) over the 2-year treatment period. Adverse events and serious adverse events were similar in both groups. Three study participants died. In the placebo group, one (1%) patient died from acute respiratory distress syndrome due to SARS-CoV-2 and one (1%) from cardiac arrest after severe dehydration following diarrhoea with hypotension, acute kidney injury, and metabolic acidosis. In the sodium bicarbonate group, one (1%) patient had sudden cardiac death. INTERPRETATION In adult kidney transplant recipients, correction of metabolic acidosis by treatment with sodium bicarbonate over 2 years did not affect the decline in estimated GFR. Thus, treatment with sodium bicarbonate should not be generally recommended to preserve estimated GFR (a surrogate marker for graft function) in kidney transplant recipients with chronic kidney disease who have metabolic acidosis. FUNDING Swiss National Science Foundation.
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Affiliation(s)
- Nilufar Mohebbi
- Division of Nephrology, University Hospital, Zurich, Switzerland.
| | - Alexander Ritter
- Division of Nephrology, University Hospital, Zurich, Switzerland
| | - Anna Wiegand
- Division of Nephrology, University Hospital, Zurich, Switzerland
| | | | - Suzan Dahdal
- Division of Nephrology and Hypertension, Inselspital, Bern, Switzerland
| | - Daniel Sidler
- Division of Nephrology and Hypertension, Inselspital, Bern, Switzerland
| | | | - Karine Hadaya
- Division of Nephrology and Hypertension, University Hospital, Geneva, Switzerland
| | - Thomas F Mueller
- Division of Nephrology, University Hospital, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland
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Serum Bicarbonate and Graft and Patient Outcomes Among Kidney Transplant Recipients: A Retrospective Cohort Study Evaluating Changes in Serum Bicarbonate Over Time. Kidney Med 2022; 5:100573. [PMID: 36683962 PMCID: PMC9850186 DOI: 10.1016/j.xkme.2022.100573] [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] [Indexed: 11/18/2022] Open
Abstract
Rationale & Objective Identification of treatable risk factors for kidney allograft failure is necessary to improve graft longevity. Metabolic acidosis with either low serum bicarbonate or normal serum bicarbonate (eubicarbonatemic metabolic acidosis) is implicated in native kidney disease progression but its effects in kidney transplant recipients are unclear. Study Design Retrospective cohort study. Setting & Participants An Integrated Claims-Clinical dataset of US patients with chronic kidney disease (estimated glomerular filtration rates <60 mL/min/1.73 m2) and serum bicarbonate data were used to generate a cohort of kidney transplant recipients with data from ≥1 year before and after transplantation. Primary Predictor The primary independent variable was a change in serum bicarbonate from baseline. Outcomes The primary outcomes were graft failure and all-cause mortality. The secondary outcomes were major adverse cardiac events and all-cause hospitalization. Analytical Approach We used adjusted time-dependent Cox proportional hazards models to assess the risk of graft failure, all-cause mortality, major adverse cardiac events, and time to first hospitalization. Results In this US community-based cohort of 1,915 kidney transplant recipients with a median follow-up of ∼2.5 years, each 1-mEq/L increase in serum bicarbonate was associated with significantly lower hazard of graft loss, death, major adverse cardiac events, and hospitalization by 10%, 8%, 4%, and 8%, respectively. Limitations Possible residual confounding. Conclusions In a US community-based population of kidney transplant recipients, even small incremental increases in serum bicarbonate (1 mEq/L) were significantly associated with reduced hazard of graft loss, all-cause mortality, cardiovascular events, and hospitalization. Interventional trials evaluating the potential benefits of treating metabolic acidosis in kidney transplant recipients are warranted.
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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: 1] [Impact Index Per Article: 0.5] [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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Brown DD, Carroll M, Ng DK, Levy RV, Greenbaum LA, Kaskel FJ, Furth SL, Warady BA, Melamed ML, Dauber A. Longitudinal Associations between Low Serum Bicarbonate and Linear Growth in Children with CKD. KIDNEY360 2022; 3:666-676. [PMID: 35721607 PMCID: PMC9136912 DOI: 10.34067/kid.0005402021] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 01/10/2022] [Indexed: 01/28/2023]
Abstract
Background Poor linear growth is a consequence of chronic kidney disease (CKD) that has been linked to adverse outcomes. Metabolic acidosis (MA) has been identified as a risk factor for growth failure. We investigated the longitudinal relationship between MA and linear growth in children with CKD and examined whether treatment of MA modified linear growth. Methods To describe longitudinal associations between MA and linear growth, we used serum bicarbonate levels, height measurements, and standard deviation (z scores) of children enrolled in the prospective cohort study Chronic Kidney Disease in Children. Analyses were adjusted for covariates recognized as correlating with poor growth, including demographic characteristics, glomerular filtration rate (GFR), proteinuria, calcium, phosphate, parathyroid hormone, and CKD duration. CKD diagnoses were analyzed by disease categories, nonglomerular or glomerular. Results The study population included 1082 children with CKD: 808 with nonglomerular etiologies and 274 with glomerular etiologies. Baseline serum bicarbonate levels ≤22 mEq/L were associated with worse height z scores in all children. Longitudinally, serum bicarbonate levels ≤18 and 19-22 mEq/L were associated with worse height z scores in children with nonglomerular CKD causes, with adjusted mean values of -0.39 (95% CI, -0.58 to -0.2) and -0.17 (95% CI, -0.28 to -0.05), respectively. Children with nonglomerular disease and more severe GFR impairment had a higher risk for worse height z score. A significant association was not found in children with glomerular diseases. We also investigated the potential effect of treatment of MA on height in children with a history of alkali therapy use, finding that only persistent users had a significant positive association between their height z score and higher serum bicarbonate levels. Conclusions We observed a longitudinal association between MA and lower height z score. Additionally, persistent alkali therapy use was associated with better height z scores. Future clinical trials of alkali therapy need to evaluate this relationship prospectively.
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Affiliation(s)
- Denver D. Brown
- Division of Nephrology, Children’s National Hospital, Washington, DC
| | - Megan Carroll
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Derek K. Ng
- Johns Hopkins Bloomberg School of Public Health, Baltimore, Maryland
| | - Rebecca V. Levy
- Division of Pediatric Nephrology, University of Rochester Medical Center, Rochester, New York
| | - Larry A. Greenbaum
- Division of Pediatric Nephrology, Emory University School of Medicine and Children’s Healthcare of Atlanta, Atlanta, Georgia
| | - Frederick J. Kaskel
- Division of Pediatric Nephrology, The Children’s Hospital at Montefiore, Bronx, New York
| | - Susan L. Furth
- Division of Pediatric Nephrology, The Children’s Hospital of Philadelphia, Philadelphia, Pennsylvania
| | - Bradley A. Warady
- Division of Pediatric Nephrology, Children’s Mercy Hospital, Kansas City, Missouri
| | - Michal L. Melamed
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York
| | - Andrew Dauber
- Division of Endocrinology, Children’s National Hospital, Washington, DC
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How MDRD (and CKD-epi and Cystatin C) eGFRs Obscure Interpretation of Kidney Transplant Studies. Transplantation 2022; 106:432-435. [PMID: 33756545 DOI: 10.1097/tp.0000000000003769] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
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10
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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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12
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Association of serum bicarbonate with graft survival and mortality in kidney transplant recipients. J Nephrol 2021; 35:619-627. [PMID: 34843097 DOI: 10.1007/s40620-021-01197-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2021] [Accepted: 11/02/2021] [Indexed: 10/19/2022]
Abstract
BACKGROUND Metabolic acidosis is an independent risk factor for kidney disease progression with a high prevalence after kidney transplantation (KTx). Remarkably, it is still unclear if there is an impact of metabolic acidosis on graft function and death after KTx. Thus, we wanted to investigate if serum bicarbonate is associated with long-term graft outcome and mortality after KTx. METHODS We performed a single-center retrospective study including adult de novo KTx patients between 1999 and 2015. Cox proportional hazard model was used to analyze a possible association between time-dependent serum bicarbonate measurements and graft failure or death. RESULTS Four hundred thirty KTRs were included in the analysis with a mean age of 50.9 ± 13.4 years. Mean observation time was 4.7 ± 2.8 years. Two hundred eighty-four (66%) patients were male and 318 (74%) had received a deceased donor kidney transplant. Mean bicarbonate and eGFR levels 1 year post-transplant amounted to 22.9 ± 3.1 mEq/L and 61 ± 26 ml/min/1.73 m2, respectively. Prevalence of metabolic acidosis was 31% 1 year after transplantation. Fourteen (3%) patients died and 31 (7%) suffered from graft failure. Higher bicarbonate levels were associated with significantly lower hazards for graft failure (Hazard Ratio (HR) = 0.88; 95% Confidence Interval (CI): 0.79-0.98) and mortality (HR = 0.79; 95% CI 0.66-0.93) after adjusting for potential confounders such as age, donor type and time-varying eGFR. CONCLUSIONS Our analysis showed that higher serum bicarbonate levels are positively associated with long-term graft and patient survival in kidney transplant recipients. Thus, serum bicarbonate may serve as a predictor and independent risk factor for graft and patient outcome after KTx as has been previously shown for patients with CKD.
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13
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Collister D, Ferguson TW, Funk SE, Reaven NL, Mathur V, Tangri N. Metabolic Acidosis and Cardiovascular Disease in CKD. Kidney Med 2021; 3:753-761.e1. [PMID: 34746740 PMCID: PMC8551483 DOI: 10.1016/j.xkme.2021.04.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Rationale & Objective Metabolic acidosis related to chronic kidney disease (CKD) is associated with an accelerated decline in glomerular filtration rate (GFR) and the development of end-stage kidney disease. Whether metabolic acidosis is associated with cardiovascular (CV) events in patients with CKD is unclear. Study Design Retrospective cohort study. Setting & Participants The Optum De-identified Electronic Health Records Dataset, 2007–2017, was used to generate a cohort of patients with non-dialysis-dependent CKD who had at least 3 estimated GFR < 60 mL/min/1.73 m2. Patients with metabolic acidosis (serum bicarbonate 12 to <22 mEq/L) or normal serum bicarbonate (22‒29 mEq/L) at baseline were identified by 2 consecutive measurements 28‒365 days apart. Predictor Serum bicarbonate as a continuous variable. Outcome Primary outcome was a composite of major adverse cardiovascular events (MACE+). Secondary outcomes included individual components of the composite outcome. Analytical Approach Cox proportional hazards models to evaluate the association between 1-mEq/L increments in serum bicarbonate and MACE+. Results A total of 51,558 patients were evaluated, 34% had metabolic acidosis. The median follow-up period was 3.9–4.5 years, depending on the outcome assessed. The adjusted hazard ratio (HR) for MACE+ was 0.964 (95% CI, 0.961–0.968). For the individual components of incident heart failure (HF), stroke, myocardial infarction (MI), and CV death, HRs were 0.98 (95% CI, 0.97–0.98), 0.98 (95% CI, 0.97–0.99), 0.96 (95% CI, 0.96–0.97), and 0.94 (95% CI, 0.93–0.94), respectively, for every 1-mEq/L increase in serum bicarbonate. Limitations Possible residual confounding. Conclusions Metabolic acidosis in CKD is associated with an increased risk of MACE+ as well as the individual components of incident HF, stroke, MI, and CV death. Randomized controlled trials evaluating treatments for the correction of metabolic acidosis in CKD to prevent CV events are needed.
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Affiliation(s)
- David Collister
- Department of Medicine, McMaster University, Hamilton, ON, Canada
| | - Thomas W Ferguson
- Department of Internal Medicine, Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB, Canada
| | | | | | | | - Navdeep Tangri
- Department of Internal Medicine, Faculty of Health Sciences, Max Rady College of Medicine, University of Manitoba, Winnipeg, MB, Canada
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14
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Bussalino E, Panaro L, Marsano L, Bellino D, Ravera M, Paoletti E. Prevalence and clinical correlates of hyperkalemia in stable kidney transplant recipients. Intern Emerg Med 2021; 16:1787-1792. [PMID: 33544373 DOI: 10.1007/s11739-021-02649-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2020] [Accepted: 01/19/2021] [Indexed: 12/28/2022]
Abstract
Although hyperkalemia (HK) is often associated with adverse clinical outcomes in renal patients, few studies are available in the setting of kidney transplantation. Therefore, we evaluated prevalence and clinical correlates of HK in stable kidney transplant recipients (KTRs) on standard of care immunosuppressive therapy. We studied 160 stable KTRs (post-transplant vintage 46.6 ± 16.6 months), most of whom (96.2%) on calcineurin inhibitor (CNI)-based immunosuppressive therapy. HK was defined as plasma potassium levels above 5 mEq/L, confirmed in two consecutive samples. Office blood pressure was measured, and renal graft function was expressed by estimated glomerular filtration rate (eGFR), calculated according to the CKD-EPI formula. HK prevalence was 8.8%, and plasma K above 5.5 mEq/L was found in 2.5% of all KTRs. In the univariate logistic regression analysis HK was significantly associated with serum urea concentration (OR 1.03, 95% CI 1.01-1.05 for each 1 mg/dL increase), tCO2 (OR 0.77, 95% CI 0.66-0.90 for each 1 mmol/L increase), the presence of arterial hypertension (OR 4.01, 95% CI 1.3-12.64), the use of RAAS inhibitors (OR 5.26, 95% CI 1.6-17.7), and eGFR less than 30 ml/min/1.73 m2 (OR 7.51, 95% CI 2.37-23.77). By multivariable backward stepwise regression analysis, the presence of metabolic acidosis (OR 0.83, 95% CI 0.69-0.99, P = 0.04), arterial hypertension (OR 4.65 95% CI 1.01-17.46 P = 0.03), and to be administered RAAS inhibitors (OR 6.11, 95% CI 1.03-25.96 P = 0.03) remained significantly associated with HK. We conclude that in stable KTRs the prevalence of HK is about 9%, slightly lower than previously reported. Moreover, it is not associated with eGFR, but with metabolic acidosis, arterial hypertension, and the use of RAAS inhibitors.
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Affiliation(s)
- Elisabetta Bussalino
- Nephrology, Dialysis, and Transplantation, University of Genoa, and Policlinico San Martino, Largo R. Benzi 10, 16132, Genova, Italy
| | - Laura Panaro
- Nephrology, Dialysis, and Transplantation, University of Genoa, and Policlinico San Martino, Largo R. Benzi 10, 16132, Genova, Italy
| | - Luigina Marsano
- Nephrology, Dialysis, and Transplantation, University of Genoa, and Policlinico San Martino, Largo R. Benzi 10, 16132, Genova, Italy
| | - Diego Bellino
- Nephrology, Dialysis, and Transplantation, University of Genoa, and Policlinico San Martino, Largo R. Benzi 10, 16132, Genova, Italy
| | - Maura Ravera
- Nephrology, Dialysis, and Transplantation, University of Genoa, and Policlinico San Martino, Largo R. Benzi 10, 16132, Genova, Italy
| | - Ernesto Paoletti
- Nephrology, Dialysis, and Transplantation, University of Genoa, and Policlinico San Martino, Largo R. Benzi 10, 16132, Genova, Italy.
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15
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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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16
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George K, Upadhyay AD, Subbiah AK, Yadav RK, Mahajan S, Bhowmik D, Agarwal SK, Bagchi S. Metabolic acidosis in the initial 6 months after renal transplantation: A prospective study. Nephrology (Carlton) 2021; 27:90-96. [PMID: 34302717 DOI: 10.1111/nep.13954] [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: 04/26/2021] [Revised: 07/13/2021] [Accepted: 07/14/2021] [Indexed: 11/30/2022]
Abstract
BACKGROUND There is limited information about the incidence of metabolic acidosis (MA) after renal transplantation. This single centre prospective study aimed to delineate the incidence and risk factors of MA in the first 6 months after renal transplantation (RTX). DESIGN, SETTING, PARTICIPANTS AND MEASUREMENTS Patients who underwent RTX between November 2018 and July 2020 were monitored with weekly measurement of serum bicarbonate level for 6 months and those who were diagnosed with MA were evaluated further to characterize the type of MA. RESULTS One hundred and twenty-five patients were included in the study, 89 (71.2%) of whom developed MA. Seventy-two patients developed MA in the first month, 11 during the 2-3 months and 6 between 4 and 6 months after transplantation. Of the 89 patients, 55(61.8%) had type 1 renal tubular acidosis (T1RTA), 27 (30.3%) had type 2 RTA (T2RTA) and 7 (7.9%) type 4 RTA (T4RTA). Two patient who had T1RTA, subsequently developed high anion gap MA following severe graft rejection. On stepwise multivariate regression analysis, serum creatinine at time of diagnosis of MA [OR (95% CI): 12.02 (1.79 to 80.59), p = .01] and high tacrolimus C0 levels [OR (95% CI): 2.43 (1.0 to 5.90), p = .049], were independent risk factors for MA. CONCLUSION There is a high incidence of MA in the initial 6 months post-transplant with serum creatinine and high tacrolimus C0 levels being independent risk factors.
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Affiliation(s)
- Kristin George
- Department of Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | - Ashish Datt Upadhyay
- Department of Biostatistics, All India Institute of Medical Sciences, New Delhi, India
| | - Arun Kumar Subbiah
- Department of Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | - Raj Kanwar Yadav
- Department of Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | - Sandeep Mahajan
- Department of Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | - Dipankar Bhowmik
- Department of Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | - Sanjay Kumar Agarwal
- Department of Nephrology, All India Institute of Medical Sciences, New Delhi, India
| | - Soumita Bagchi
- Department of Nephrology, All India Institute of Medical Sciences, New Delhi, India
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17
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Silva PHI, Wiegand A, Daryadel A, Russo G, Ritter A, Gaspert A, Wüthrich RP, Wagner CA, Mohebbi N. Acidosis and alkali therapy in patients with kidney transplant is associated with transcriptional changes and altered abundance of genes involved in cell metabolism and acid-base balance. Nephrol Dial Transplant 2021; 36:1806-1820. [PMID: 34240183 DOI: 10.1093/ndt/gfab210] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2021] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Metabolic acidosis occurs frequently in patients with kidney transplant and is associated with higher risk for and accelerated loss of graft function. To date, it is not known whether alkali therapy in these patients improves kidney function and whether acidosis and its therapy is associated with altered expression of proteins involved in renal acid-base metabolism. METHODS We collected retrospectively kidney biopsies from 22 patients. Of these patients, 9 had no acidosis, 9 had metabolic acidosis (plasma HCO3- < 22 mmol/l), and 4 had acidosis and received alkali therapy. We performed transcriptome analysis and immunohistochemistry for proteins involved in renal acid-base handling. RESULTS We found the expression of 40 transcripts significantly changed between kidneys from non-acidotic and acidotic patients. These genes are mostly involved in proximal tubule amino acid and lipid metabolism and energy homeostasis. Three transcripts were fully recovered by alkali therapy: the Kir4.2 K+-channel, an important regulator of proximal tubule HCO3--metabolism and transport, ACADSB and SHMT1, genes involved in beta-oxidation and methionine metabolism. Immunohistochemistry showed reduced staining for the proximal tubule NBCe1 HCO3- transporter in kidneys from acidotic patients that recovered with alkali therapy. In addition, the HCO3-exchanger pendrin was affected by acidosis and alkali therapy. CONCLUSIONS Metabolic acidosis in kidney transplant recipients is associated with alterations in the renal transcriptome that are partly restored by alkali therapy. Acid-base transport proteins mostly from proximal tubule were also affected by acidosis and alkali therapy suggesting that the downregulation of critical players contributes to metabolic acidosis in these patients.
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Affiliation(s)
- Pedro H Imenez Silva
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Switzerland
| | - Anna Wiegand
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Arezoo Daryadel
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Switzerland
| | - Giancarlo Russo
- Functional Genomics Center Zürich, University of Zürich and ETH Zürich, Zürich, Switzerland
| | - Alexander Ritter
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Ariana Gaspert
- Department of Pathology and Molecular Pathology, University Hospital Zurich, Zurich, Switzerland
| | - Rudolf P Wüthrich
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
| | - Carsten A Wagner
- Institute of Physiology, University of Zurich, Zurich, Switzerland.,National Center of Competence in Research NCCR Kidney.CH, Switzerland
| | - Nilufar Mohebbi
- Division of Nephrology, University Hospital Zurich, Zurich, Switzerland
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18
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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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19
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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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20
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Wang A, Tian X, Gu H, Zuo Y, Meng X, Lv W, Li H, Wang Y. CO 2 combining power and outcomes in patients with acute ischaemic stroke or transient ischaemic attack. Stroke Vasc Neurol 2020; 6:252-259. [PMID: 33298534 PMCID: PMC8258072 DOI: 10.1136/svn-2020-000476] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/13/2020] [Accepted: 11/14/2020] [Indexed: 12/20/2022] Open
Abstract
Background and purpose The clinical significance of carbon dioxide combining power (CO2CP) in ischaemic cerebrovascular disease is not well established, and the role of CO2CP in the prognosis of acute ischaemic stroke (AIS) or transient ischaemic attack (TIA) has not been reported. The objective of the study was to investigate the associations between CO2CP and clinical outcomes in patients with AIS or TIA. Methods Data were derived from the China National Stroke Registry III. Patients were classified into five groups by quintiles of CO2CP levels and three groups according to the normal range of CO2CP (23–29 mmol/L). Multivariable Cox and logistic regressions were adopted to explore the associations of CO2CP levels with all-cause death and poor functional outcomes (modified Rankin Scale (mRS) 3–6/2–6) at 3 months and 1 year. Results Among 9531 patients included in the study, the median (IQR) CO2CP was 24.9 (23.0–27.0) mmol/L. After adjustment for potential confounders, patients in the first CO2CP quintile (21.1–23.3 mmol/L) had higher risk of all-cause death and poor functional outcomes (mRS score of 3–6/2–6) (HR or OR with 95% CI 2.37 (1.32 to 4.25), 1.49 (1.20 to 1.83) and 1.21 (1.03 to 1.42), respectively) compared with those in the fourth quintile. Similar results were found for outcomes at 1 year. Furthermore, all associations were also significant when CO2CP was <23 mmol/L compared with CO2CP of 23–29 mmol/L. Conclusions Decreased CO2CP was associated with high risk of all-cause death and poor functional outcomes in patients with AIS or TIA.
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Affiliation(s)
- Anxin Wang
- China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Xue Tian
- Department of Epidemiology and Health Statistics, School of Public Health, Capital Medical University, Beijing, China.,Beijing Municipal Key Laboratory of Clinical Epidemiology, Beijing, China
| | - Hongqiu Gu
- China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yingting Zuo
- Department of Epidemiology and Health Statistics, School of Public Health, Capital Medical University, Beijing, China.,Beijing Municipal Key Laboratory of Clinical Epidemiology, Beijing, China
| | - Xia Meng
- China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Wei Lv
- China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Hao Li
- China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China.,Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yongjun Wang
- China National Clinical Research Center for Neurological Diseases, Beijing Tiantan Hospital, Capital Medical University, Beijing, China .,Department of Neurology, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
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21
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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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Gojowy D, Skiba K, Bartmanska M, Kolonko A, Wiecek A, Adamczak M. Is Metabolic Acidosis a Novel Risk Factor for a Long-Term Graft Survival in Patients after Kidney Transplantation? Kidney Blood Press Res 2020; 45:702-712. [PMID: 32799205 DOI: 10.1159/000508476] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2020] [Accepted: 05/06/2020] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Results of both experimental and clinical studies suggest that metabolic acidosis (MA) contributes to the progression of chronic kidney disease (CKD) and mortality in CKD patients. It is unknown whether the same relationship exists in kidney transplantation (KTx) patients. The aim of this observational study was to examine this relationship between MA and both mortality and renal outcomes in patients after KTx. METHODS Four hundred eighty-six (290 male; 196 female) patients aged 48 ± 12 years, at least 1 year after KTx, were analyzed. Blood HCO3- was measured, and patients were then observed over 3 years. MA was defined as the blood HCO3- concentration <22 mmol/L. The end points of survival analysis were death and initiation of dialysis therapy. In patients who did not reach the above-mentioned end points, the difference between final (after 3 years of follow-up) and initial estimated glomerular filtration rate (eGFR) was calculated. RESULTS MA was initially diagnosed in 57 (12%) patients after KTx. Three-year patient survival was 89.5% in the MA group and 97.4% in the non-MA group (p = 0.001). Three-year graft survival was 73.7% for patients with MA and 93.0% for patients without MA (p < 0.001). In patients with MA who did not reach study end points, blood bicarbonate concentration at baseline correlated positively with a change in eGFR (R = 0.48, p = 0.002, n = 36). Such a correlation was not found in patients without MA (n = 388). CONCLUSIONS (1) MA significantly increases the risk of mortality in patients after KTx. (2) The intensity of MA may be associated with progression of transplanted kidney dysfunction in KTx patients.
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Affiliation(s)
- Damian Gojowy
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia, Katowice, Poland
| | - Katarzyna Skiba
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia, Katowice, Poland
| | - Magdalena Bartmanska
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia, Katowice, Poland
| | - Aureliusz Kolonko
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia, Katowice, Poland
| | - Andrzej Wiecek
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia, Katowice, Poland
| | - Marcin Adamczak
- Department of Nephrology, Transplantation and Internal Medicine, Medical University of Silesia, Katowice, Poland,
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Wesson DE. Serum bicarbonate as a cardiovascular risk factor: evolving from 'non-traditional'? Nephrol Dial Transplant 2020; 35:1282-1285. [PMID: 32003809 DOI: 10.1093/ndt/gfz297] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2019] [Accepted: 12/11/2019] [Indexed: 11/13/2022] Open
Affiliation(s)
- Donald E Wesson
- Baylor Scott and White Health and Wellness Center, Dallas, TX, USA.,Department of Internal Medicine, Texas A&M College of Medicine, Dallas, TX, USA
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Farouk SS, Rein JL. The Many Faces of Calcineurin Inhibitor Toxicity-What the FK? Adv Chronic Kidney Dis 2020; 27:56-66. [PMID: 32147003 DOI: 10.1053/j.ackd.2019.08.006] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2019] [Accepted: 08/01/2019] [Indexed: 02/07/2023]
Abstract
Calcineurin inhibitors (CNIs) are both the savior and Achilles' heel of kidney transplantation. Although CNIs have significantly reduced rates of acute rejection, their numerous toxicities can plague kidney transplant recipients. By 10 years, virtually all allografts will have evidence of CNI nephrotoxicity. CNIs have been strongly associated with hypertension, dyslipidemia, and new onset of diabetes after transplantation-significantly contributing to cardiovascular risk in the kidney transplant recipient. Multiple electrolyte derangements including hyperkalemia, hypomagnesemia, hypercalciuria, metabolic acidosis, and hyperuricemia may be challenging to manage for the clinician. Finally, CNI-associated tremor, gingival hyperplasia, and defects in hair growth can have a significant impact on the transplant recipient's quality of life. In this review, the authors briefly discuss the pharmacokinetics of CNI and discuss the numerous clinically relevant toxicities of commonly used CNIs, cyclosporine and tacrolimus.
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Woodell TB, Ix JH. Is Metabolic Acidosis a Friend or Foe for Cardiovascular Disease in Kidney Transplant Recipients? Am J Kidney Dis 2019; 73:465-466. [PMID: 30773237 DOI: 10.1053/j.ajkd.2019.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2018] [Accepted: 01/04/2019] [Indexed: 11/11/2022]
Affiliation(s)
- Tyler B Woodell
- Division of Nephrology-Hypertension, Department of Medicine, University of California San Diego, San Diego, CA
| | - Joachim H Ix
- Division of Nephrology-Hypertension, Department of Medicine, University of California San Diego, San Diego, CA; Nephrology Section, Veterans Affairs San Diego Healthcare System, La Jolla, CA; Division of Preventive Medicine, Department of Family Medicine and Public Health, University of California San Diego, San Diego, CA.
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