Active smoking in urban households: An association between urinary cotinine metabolite level and serum eGFR concentration

INTRODUCTION

Smoking stands as a primary contributor to preventable deaths globally and is linked to an increased risk of developing kidney failure and other diseases. A few studies have focused on the negative correlation between serum cotinine and estimated glomerular filtration rate (eGFR), indicating decreased kidney function. This study investigated the associations between urinary cotinine metabolite concentration and serum eGFR among active smokers in urban households.

METHODS

This was a cross-sectional study of active smokers in urban households' community Bangkok, Thailand from January to April 2023. The study involved 85 participants aged ≥18 years who were active smokers. Both urinary cotinine and serum eGFR concentrations were used as biomarkers. Independent sample t-tests were used to compare the urinary cotinine metabolite based on differences in the characteristic variable. We used multiple linear regression to test the association between cotinine metabolite and characteristics variables. Spearman's analysis was used to test the correlation between cotinine metabolite and eGFR concentration.

RESULTS

The association between urinary cotinine metabolite and serum eGFR concentration decreased with increasing cotinine concentrations (r= -0.223, p=0.041), suggesting a decline in kidney function. However, this study found no significant difference between urinary cotinine metabolite and characteristic variables (p>0.05). Additionally, those who smoked for ≥10 years (117.40 ± 89.80 ng/mL), smoked ≥10 cigarettes per day (117.40 ± 89.80 ng/mL) and used conventional cigarettes (124.53 ± 115.10 ng/mL). The results of the multiple linear regression models analysis indicated that those who were smokers for ≥10 years (β=0.076; 95% CI: -31.575-59.715) and those who were smoked ≥10 cigarettes/day (β=0.126; 95% CI: -65.636-18.150) were not associated with urinary cotinine metabolite level.

CONCLUSIONS

This study shows that the urinary cotinine metabolite level is associated with serum eGFR concentration among active smokers in urban households. The current study suggests that clinical identification and a prospective cohort study are needed before robust conclusions about how tobacco affects kidney efficiency.

Whole-body water mass and kidney function: a Mendelian randomization study

Background

The morbidity and mortality of chronic kidney disease (CKD) are increasing worldwide, making it a serious public health problem. Although a potential correlation between body water content and CKD progression has been suggested, the presence of a causal association remains uncertain. This study aimed to determine the causal effect of body water content on kidney function.

Methods

Genome-wide association study summary data sourced from UK Biobank were used to evaluate single-nucleotide polymorphisms (SNPs) associated with whole-body water mass (BWM). The summary statistics pertaining to kidney function were extracted from the CKDGen consortium. The primary kidney function outcome measures included estimated glomerular filtration rate (eGFR), albuminuria, CKD stages 3-5, and rapid progression to CKD (CKDi25). Two-sample Mendelian randomization (MR) analysis estimated a potential causal relationship between the BWM and kidney function. The inverse variance weighted MR method was used as the primary analysis, accompanied by several sensitive MR analyses.

Results

The increase of BWM exhibited a correlation with a reduction in eGFR (β = -0.02; P = 6.95 × 10-16). Excluding 13 SNPs responsible for pleiotropy (P = 0.05), the increase of BWM was also associated with the decrease of the ratio of urinary albumin to creatinine (β = -0.16; P = 5.91 × 10-36). For each standard deviation increase in BWM, the risk of CKD stages 3-5 increases by 32% (OR, 1.32; 95% CI, 1.19-1.47; P = 1.43 × 10-7), and the risk of CKDi25 increases by 22% (OR, 1.22; 95% CI, 1.07-1.38; P = 0.002).

Conclusion

The increase of BWM is associated with impaired kidney function. Proactively managing body water content is of great significance in preventing the progression of CKD.

Alzheimer's disease cerebrospinal fluid biomarkers and kidney function in normal and cognitively impaired older adults

INTRODUCTION

Recent Alzheimer's disease (AD) clinical trials have used cerebrospinal fluid (CSF) biomarker levels for screening and enrollment. Preliminary evidence suggests that AD risk is related to impaired renal function. The impact of kidney function on commonly used AD biomarkers remains unknown.

METHODS

Participants in studies conducted at the Goizueta Alzheimer's Disease Research Center (N = 973) had measurements of serum creatinine and CSF AD biomarkers. General linear models and individual data were used to assess the relationships between biomarkers and eGFR.

RESULTS

Lower estimated glomerular filtration rate (eGFR) was associated with lower amyloid beta (Aβ)42/tau ratio (p < 0.0001) and Aβ42 (p = 0.002) and higher tau (p < 0.0001) and p-tau (p = 0.0002). The impact of eGFR on AD biomarker levels was more robust in individuals with cognitive impairment (all p-values were < 0.005).

DISCUSSION

The association between eGFR and CSF AD biomarkers has a significant impact that varies by cognitive status. Future studies exploring this impact on the pathogenesis of AD and related biomarkers are needed.

Highlights

There is a significant association between Alzheimer's disease (AD) cerebrospinal fluid (CSF) biomarkers and both estimated glomerular filtration rate (eGFR) and mild cognitive impairment (MCI).Kidney function influences CSF biomarker levels in individuals with normal cognitive function and those with MCI.The impact of kidney function on AD biomarker levels is more pronounced in individuals with cognitive impairment.The variation in CSF tau levels is independent of cardiovascular factors and is likely directly related to kidney function.Tau may have a possible role in both kidney and cognitive function.

Effects of Sacubitril/Valsartan Across the Spectrum of Renal Impairment in Patients With Heart Failure

BACKGROUND

The Kidney Disease Improving Global Outcomes (KDIGO) classification integrates both estimated glomerular filtration rate(eGFR) and urine-albumin-creatinine-ratio to stratify risk more comprehensively in patients with chronic kidney disease. There are limited data assessing whether this classification system is associated with prognosis and treatment response in heart failure populations.

METHODS

PARADIGM-HF was a global RCT evaluating sacubitril/valsartan vs. enalapril in patients with HFrEF. Patients were classified according to low, moderate, and high/very high KDIGO risk. Treatment responses were assessed according to baseline KDIGO risk. The primary outcome was a composite of CV death or HF hospitalization. A renal composite outcome was defined as sustained decline in eGFR by ≥40% or end stage kidney disease.

RESULTS

Among 1,910 (23% of total) participants with available data, 42%, 32%, and 26% were classified as low, moderate, and high/very high KDIGO risk, respectively. Patients in the highest KDIGO risk categories experienced the highest rates of the primary composite outcome (7.6[6.5-9.0], 9.4[7.9-11.2], 14.9[12.7-17.6] per 100py; P<0.001). Sacubitril/valsartan had a similar safety profile and similarly reduced the risk of both the primary outcome (PInteraction=0.31) and the renal composite outcome (PInteraction=0.50) across the spectrum of KDIGO risk.

CONCLUSION

One in 4 patients with HFrEF were classified as at least high KDIGO kidney risk; these individuals faced concordantly the highest risks of CV events. Sacubitril/valsartan exhibited consistent CV and kidney protective benefits as well as safety across the spectrum of baseline kidney risk. These data further support initiation of sacubitril/valsartan in HFrEF across a broad range of kidney risk.

Dependence of Renal Uptake on Kidney Function in [68Ga]Ga-PSMA-11 PET/CT Imaging

(1) Background: PSMA ligand PET/CT is increasingly important for diagnostics of prostate cancer and other tumor diseases. In particular, the radiopharmaceutical [68Ga]Ga-PSMA-11 is widely used. Besides its tumor-specific binding, the uptake within the kidneys is dominant and seems to visualize the renal cortex specifically. Kidney diseases may alter the uptake of radiopharmaceuticals. Therefore, the correlation between renal uptake in PET/CT imaging and renal function should be investigated. (2) Methods: A group of 103 male patients were retrospectively evaluated for eGFR according to the CKD-EPI equation, tracer uptake intensity (SUVmax, SUVpeak, SUVmean), the molecular volume of the renal cortex, morphological kidney size, and total renal uptake. Manual and three different computer-assisted contouring methods (thresholds at 50% of SUVmax, 30% of SUVmax, and absolute SUV of 20) were used for measurements. Correlations between parameters were calculated using linear regression models. (3) Results: Renal SUVmax, SUVpeak, and SUVmean do not correlate with eGFR for manual or computer-assisted measurements. In contrast, molecular cortex volume shows a moderate correlation with eGFR (R2 = 0.231, p < 0.001), superior to morphological kidney size. A contouring threshold of 30% of SUVmax outperformed the other settings for renal cortex volume and total renal uptake. (4) Conclusions: Renal uptake of [68Ga]Ga-PSMA-11 cannot predict eGFR, but the functional renal cortex can be quantified by PET/CT imaging.

Associations Between Dietary Patterns and Kidney Health Assessed in the Population-Based CHRIS Study Using Reduced Rank Regression

OBJECTIVE

While diet plays a key role in chronic kidney disease (CKD) management, the potential for diet to impact CKD prevention in the general population is less clear. Using a priori knowledge, we derived disease-related dietary patterns (DPs) through reduced rank regression (RRR) and investigated associations with kidney function, separately focusing on generally healthy individuals and those with self-reported kidney diseases, hypertension, or diabetes mellitus.

METHODS

Eight thousand six hundred eighty-six participants from the population-based Cooperative Health Research in South Tyrol study were split into a group free of kidney disease, hypertension and diabetes (n = 6,133) and a group with any of the 3 conditions (n = 2,553). Diet was assessed through the self-administered Global Allergy and Asthma Network of Excellence food frequency questionnaire and DPs were derived through RRR selecting food frequency questionnaire-derived sodium, potassium, phosphorus, and protein intake as mediators. Outcomes were creatinine-based estimated glomerular filtration rate, urinary albumin-to-creatinine ratio, CKD and microalbuminuria. Multiple linear and logistic models were used to assess associations between RRR-based DPs and kidney outcomes separately in the 2 analytic groups.

RESULTS

We identified 3 DPs, where high adherence reflected high levels of all nutrients (DP1), high potassium-phosphorus and low protein-sodium levels (DP2), and low potassium-sodium and high protein-phosphorus levels (DP3), respectively. We observed heterogeneous associations with kidney outcomes, varying by analytic group and sex. Kidney outcomes were much more strongly associated with DPs than with single nutrients.

CONCLUSION

RRR is a feasible approach to estimate disease-related DPs and explore the combined effects of nutrients on kidney health. Heterogeneous associations across kidney outcomes suggest possible specificity to kidney function or damage. In individuals reporting kidney disease, hypertension or diabetes, specific dietary habits were associated with better kidney health, indicating that disease-specific dietary interventions can be effective for disease control.

A systematic review assessing the potential use of cystatin c as a biomarker for kidney disease in people living with HIV on antiretroviral therapy

The introduction of antiretroviral therapy (ART) has significantly prolonged the lifespan of people living with human immunodeficiency virus (PLWH). However, the sustained use of this drug regimen has also been associated with a cluster of metabolic anomalies, including renal toxicity, which can lead to the development of kidney diseases. In this study, we reviewed studies examining kidney disease in PLWH sourced from electronic databases such as PubMed/MEDLINE, Scopus, and Google Scholar, as well as gray literature. The narrative synthesis of data from these clinical studies demonstrated that the serum levels of cystatin C remained unchanged or were not affected in PLWH on ART, while the creatinine-based glomerular filtration rate (GFR) fluctuated. In fact, some of the included studies showed that the creatinine-based GFR was increased in PLWH taking tenofovir disoproxil fumarate-containing ART, perhaps indicating that the use of both cystatin C- and creatinine-based GFRs is vital to monitor the development of kidney disease in PLWH. Clinical data summarized within this study indicate the potential detrimental effects of tenofovir-based ART regimens in causing renal tubular injury, while highlighting the possible beneficial effects of dolutegravir-based ART on improving the kidney function in PLWH. However, the summarized literature remains limited, while further clinical studies are required to provide insights into the potential use of cystatin C as a biomarker for kidney disease in PLWH.

Endovascular recanalization for pediatric hypertension secondary to total renal artery occlusion

PURPOSE

To assess the feasibility and efficacy of percutaneous transluminal renal angioplasty (PTRA) for pediatric renovascular hypertension (RVH) secondary to total renal artery occlusion (RAO).

METHODS

From 2011 to 2021, 13 pediatric patients with RVH confirmed with 14 occluded renal artery lesions were reviewed. The mean age was11.2 years (range 4 to 16). Nine lesions involved main artery occlusion, while five lesions featured branch occlusion. Blood Pressure Ratio (BPR) was defined as the ratio of the actual BP value to the 95th percentile value adjusted for age, gender, and height.

RESULTS

PTRA was performed on nine patients (9/13, 69%). Technical success was achieved in five patients (5/9, 56%), with stent placement in two children (2/9, 22%). During the 12-month follow-up, restenosis was identified in two stent-receiving patients at the 12-month follow-up visit (2/9, 22%). Mean systolic BPR decreased from 1.20 ± 0.07 to 0.96 ± 0.06 (p = 0.003), mean diastolic BPR decreased from 1.19 ± 0.07 to 0.95±0.08 (p = 0.005) and the number of required medications decreased from 3.8 ± 0.8 to 2.4 ± 0.9 (p = 0.052) following PTRA. Subsequent to PTRA, the mean GFR of the occluded kidney improved from 19.5 ± 12.3 mL/ min to 36.3 ± 10.8 mL/ min (p = 0.007) and the mean longitudinal dimension of the affected kidneys significantly increased from 8.2 ± 1.5 cm to 9.2 ± 1.7 cm (p = 0.006).

CONCLUSIONS

Endovascular treatment is feasible for pediatric RAO, results in acceptable BP control and preserves renal function.

The Role of Dietary Acid Load on Progression of Estimated Glomerular Filtration Rate Among Individuals Diagnosed With Chronic Kidney Disease

OBJECTIVE

Individuals with chronic kidney disease (CKD) are at an increased risk for developing metabolic acidosis. Metabolic acidosis has been shown to worsen kidney function and exacerbate systemic inflammation. Diets high in protein foods can exacerbate metabolic acidosis as protein foods tend to be more acidic, while fruits and vegetables are more alkalotic. The main objective of this systematic review was to determine if higher consumption of fruits and vegetables in adults with CKD stages 1-5 reduces the rate of decline of estimated glomerular filtration rate.

METHODS

Searches of Cumulated Index to Nursing and Allied Health Literature (CINAHL -Elton B. Stephens Company [EBSCO]), Cochrane Library (Wiley), Dissertation & Thesis Global (ProQuest), Embase (Elsevier), Medline (OVID), PubMed (National Library of Medicine), Scopus (Elsevier), and Web of Sciences (Clarivate) identified 1,451 articles published between January 2015 and June 2023.

RESULTS

After independent review, 7 total studies were included. Six of the studies found an association between dietary acid load and progression of CKD.

CONCLUSIONS

Dietary counseling focusing on decreasing dietary acid load may be beneficial for individuals with CKD.

Physical exercise: a polypill against chronic kidney disease

We are currently facing a pandemic of physical inactivity that might contribute to the growing prevalence of chronic kidney disease (CKD). Here, we summarize currently available evidence on the association between physical activity and CKD, and also review the effects of exercise intervention in affected patients. Physical activity/exercise might act as a polypill against CKD, preventing its development or even exerting beneficial effects once it is established (i.e. improvements in patients' physical fitness and cardiovascular risk, as well as in kidney function). Exercise benefits are also found at advanced CKD stages or in patients under hemodialysis. The biological mechanisms behind the clinical evidence are also discussed. An active lifestyle appears as a cornerstone in CKD prevention and management.

A Holistic Framework for the Evaluation of Kidney Function in a Gender-Diverse Landscape

The most commonly used equations to estimate glomerular filtration rate incorporate a binary male-female sex coefficient, which has important implications for the care of transgender, gender-diverse, and non-binary (TGD) people. Whether "sex assigned at birth" or a binary "gender identity" is most appropriate for the computation of estimated glomerular filtration rate (eGFR) is unknown. Furthermore, the use of gender-affirming hormone therapy (GAHT) for the development of physical changes to align TGD people with their affirmed gender is increasingly common, and may result in changes in serum creatinine and cystatin C, biomarkers commonly used to estimate glomerular filtration rate. The paucity of current literature evaluating chronic kidney disease (CKD) prevalence and outcomes in TGD individuals on GAHT makes it difficult to assess any effects of GAHT on kidney function. Whether alterations in serum creatinine reflect changes in glomerular filtration rate or simply changes in muscle mass is unknown. Therefore, we propose a holistic framework to evaluate kidney function in TGD people. The framework focuses on kidney disease prevalence, risk factors, sex hormones, eGFR, other kidney function assessment tools, and the mitigation of health inequities in TGD people.

Kidney Function Trajectories and Right Heart Failure Following LVAD Implantation

BACKGROUND

Preoperative kidney dysfunction is a risk factor for right heart failure (RHF) after implantation of a left ventricular assist device (LVAD). However, characteristic kidney function trajectories before and after post-LVAD RHF are uncertain, so we investigated this.

METHODS AND RESULTS

We identified individuals who received primary continuous-flow LVAD implantation from July 1, 2014 to December 31, 2017 in the Interagency Registry for Mechanically Assisted Circulatory Support (INTERMACS) data set. Incident RHF was ascertained using the INTERMACS definition at 1 and 3 months and classified as transient or persistent. Kidney function trajectories before and after RHF onset, and relationships of baseline kidney function with RHF risk at the different time points, were assessed. We identified 8076 LVAD recipients who met inclusion criteria. Incident RHF was present at 1 month in 26.4%. There were 4850 individuals with follow-up at 3 months, with incident RHF in 4.2%. Kidney function trajectories differed from pre-LVAD implantation to 1-month follow-up by RHF category, with those developing persistent RHF having no improvement in baseline kidney function. For trajectories before the 3-month RHF ascertainment time, the shape was similar for those with and without RHF, with lower estimated glomerular filtration rate levels among those who developed RHF. Baseline estimated glomerular filtration rate levels below the normal range were associated with higher risk of RHF at 1 and 3 months.

CONCLUSIONS

In LVAD recipients, preimplantation kidney function and subsequent kidney function trajectories differed substantially by RHF at 1 and 3 months postimplantation, even after adjustment for several confounders. This may demonstrate bidirectional associations between kidney function and right ventricular function in LVAD recipients.

Hypohydration attenuates increases in creatinine clearance to oral protein loading and the renal hemodynamic response to exercise pressor reflex

Insufficient hydration is prevalent among free living adults. This study investigated whether hypohydration alters 1) renal functional reserve, 2) the renal hemodynamic response to the exercise pressor reflex, and 3) urine-concentrating ability during oral protein loading. In a block-randomized crossover design, 22 healthy young adults (11 females and 11 males) underwent 24-h fluid deprivation (Hypohydrated) or 24-h normal fluid consumption (Euhydrated). Renal functional reserve was assessed by oral protein loading. Renal hemodynamics during the exercise pressor reflex were assessed via Doppler ultrasound. Urine-concentrating ability was assessed via free water clearance. Creatinine clearance did not differ at 150 min postprotein consumption between conditions [Hypohydrated: 246 mL/min, 95% confidence interval (CI): 212-280; Euhydrated: 231 mL/min, 95% CI: 196-265, P = 0.2691] despite an elevated baseline in Hypohydrated (261 mL/min, 95% CI: 218-303 vs. 143 mL/min, 95% CI: 118-168, P < 0.0001). Renal artery vascular resistance was not different at baseline (P = 0.9290), but increases were attenuated in Hypohydrated versus Euhydrated at the end of handgrip (0.5 mmHg/cm/s, 95% CI: 0.4-0.7 vs. 0.8 mmHg/cm/s 95% CI: 0.6-1.1, P = 0.0203) and end occlusion (0.2 mmHg/cm/s, 95% CI: 0.1-0.3 vs. 0.4 mmHg/cm/s 95% CI: 0.3-0.6, P = 0.0127). There were no differences between conditions in free water clearance at 150 min postprotein (P = 0.3489). These data indicate that hypohydration 1) engages renal functional reserve and attenuates the ability to further increase creatinine clearance, 2) attenuates increases in renal artery vascular resistance to the exercise pressor reflex, and 3) does not further enhance nor impair urine-concentrating ability during oral protein loading.NEW & NOTEWORTHY Insufficient hydration is prevalent among free living adults. This study found that hypohydration induced by 24-h fluid deprivation engaged renal functional reserve and that oral protein loading did not further increase creatinine clearance. Hypohydration also attenuated the ability to increase renal vascular resistance during the exercise pressor reflex. In addition, hypohydration neither enhanced nor impaired urine-concentrating ability during oral protein loading. These data support the importance of mitigating hypohydration in free living adults.

Associations between inflammatory and angiogenic proteomic biomarkers, and cardiovascular events and mortality in relation to kidney function

Background

The links between chronic kidney disease (CKD) and the high burden of cardiovascular disease remain unclear. We aimed to explore the association between selected inflammatory and angiogenic biomarkers, kidney function and long-term outcome in patients with an acute coronary syndrome (ACS) and to test the hypothesis that CKD status modifies this association.

Methods

A total of 1293 ACS patients hospitalized between 2008 and 2015 were followed until 31 December 2017. Plasma was collected on days 1-3 after admission. A total of 13 biomarkers were a priori identified and analysed with two proteomic methods, proximity extension assay or multiple reaction monitoring mass spectrometry. Boxplots and multiple linear regression models were used to study associations between biomarkers and kidney function and adjusted standardized Cox regression with an interaction term for CKD was used to assess whether CKD modified the association between biomarkers and major adverse cardiovascular events and death (MACE+).

Results

The concentrations of nine biomarkers-endothelial cell-specific molecule-1 (ESM-1), fibroblast growth factor 23 (FGF-23), fractalkine (CX3CL1), interleukin-1 receptor antagonist (IL-1RA), interleukin-18 (IL-18), monocyte chemotactic protein-1 (MCP-1), placenta growth factor (PlGF), transmembrane immunoglobulin 1 (TIM-1) and vascular endothelial growth factor A (VEGFA)-were inversely associated with kidney function. ESM-1, FGF-23 and TIM-1 showed associations with MACE+. Only FGF23 remained independently associated after adjustment for the other biomarkers (hazard ratio per standard deviation increase 1.34; 95% Bonferroni corrected confidence interval 1.19-1.50). None of the biomarkers showed an interaction with CKD.

Conclusions

The concentrations of 9 of the 13 prespecified inflammatory and angiogenic proteomic biomarkers increased when kidney function declined. Only FGF-23 demonstrated an independent association with MACE+, and this association was not modified by CKD status. These findings further support FGF-23 as an independent prognostic marker in ACS patients with and without CKD.

Empagliflozin and Rapid Kidney Function Decline Incidence in Type 2 Diabetes: An Exploratory Analysis From the EMPA-REG OUTCOME Trial

Rationale & Objective

Kidney function progressively declines in most patients with type 2 diabetes (T2DM). Many develop progressive chronic kidney disease (CKD), but some experience a more rapid decline, with a greater risk of kidney failure and cardiovascular disease. In EMPA-REG OUTCOME, empagliflozin was associated with slower kidney disease progression. This post hoc analysis evaluated the effect of empagliflozin (pooled doses) on the prevalence of a "rapid decliner" phenotype, defined by an annual estimated glomerular filtration rate (eGFR) decline of >3 mL/min/1.73 m2.

Study Design

This was an exploratory analysis of EMPA-REG OUTCOME, a large randomized, double-blind, placebo-controlled trial in adults with T2DM, established cardiovascular disease and an eGFR of ≥30 mL/min/1.73 m2.

Setting & Participants

Analysis was undertaken on 6,967 participants (99.2%) in whom serial eGFR data was available.

Interventions

Patients were randomized (1:1:1) to empagliflozin 10 mg, 25 mg, or placebo in addition to standard of care.

Outcomes

Annual change in eGFR over the maintenance phase of treatment (week 4 to last value on treatment) was calculated using linear regression models. Logistic regression analysis was used to investigate differences in rapid decline between the treatment groups.

Results

Over the study period, a rapid decliner phenotype was observed in 188 (9.5%) participants receiving placebo and 134 (3.4%) receiving empagliflozin. After adjusting for other risk factors, this equated to a two-third reduction in odds (OR, 0.32; 95% CI, 0.25-0.40; P < 0.001) among participants receiving empagliflozin versus placebo. A comparable risk reduction was observed using a threshold of eGFR decline of >5 mL/min/1.73 m2/y (empagliflozin vs placebo, 43 [1.1%] vs 44 [2.2%] participants; OR, 0.47; 95% CI, 0.31-0.72; P < 0.001).

Limitations

This is a post hoc analysis of a trial undertaken in participants with T2DM and CVD. Generalization of findings to other settings remains to be established.

Conclusions

Patients receiving empagliflozin were significantly less likely to experience a rapid decline in eGFR over a median of 2.6 years of exposure to the study drug.

Funding

The Boehringer Ingelheim and Eli Lilly and Company Diabetes Alliance.

Trial Registration

clinicaltrials.gov ID: NCT01131676.

Geriatric nutritional risk index as a possible predictor of decline in kidney function in older people

Background

The Geriatric Nutritional Risk Index (GNRI) is associated with morbidity and mortality in older individuals. Our study explored the relationship between GNRI, decline in kidney function, and all-cause mortality in older individuals.

Methods

This retrospective cohort study analyzed data from participants aged ≥60 years who underwent a general health checkup between 2002 and 2018. The primary exposure was the GNRI, divided into quartiles. The primary and secondary outcomes were a decline in kidney function assessed using the five-year estimated glomerular filtration rate (eGFR) and all-cause mortality, respectively.

Results

The analysis included a total of 1,599 participants (median [interquartile range] age, 63 (61-67) years; 54% males). The mean ± standard deviation (SD) of GNRI was 114 ± 7. Compared with the highest GNRI quartile, the lower GNRI quartiles were associated with steeper five-year slopes in eGFR, with a fully adjusted beta coefficient and 95% confidence intervals (CIs) of -0.50 (-0.86. -0.14), -0.29 (-0.63. 0.05), and -0.19 (-0.53. 0.14) for the first, second, and third GNRI quartiles, respectively. The median follow-up duration was 7.4 (4.6-12.4) years. During this period, we identified 108 deaths (7.8 per 1000 person-years). The first GNRI quartile was associated with all-cause mortality compared to the highest GNRI quartile (hazard ratio and 95%CI 2.20 [1.23, 3.95]).

Conclusion

Nutritional status, as evaluated using the GNRI, was associated with five-year changes in kidney function and all-cause mortality in older individuals.

[The Outpatient Activity of the Onconephrology Clinic of Cremona in the First Semester of 2023]

Despite the rapidly growing area of onconephrology in the last decade, nephropathic patients have been rarely involved in clinical trials of cancer therapy, particularly in the case of chronic kidney disease (CKD) stage 4 (CKD4) or stage 5 (CKD5). We could offer better therapeutic opportunities to our patients thanks to the Onconephrology Clinic and the Multidisciplinary group, in which a dedicated team of specialists guarantees the highest level of possible care. In this paper, we analysed the activity of the first Italian OnconephrologyClinic, twelve years after its foundation. We studied retrospectively a cohort of 174 patients referred to our center in the last six months (from 11/01/2023 to 12/07/2023), with a total of 262 visits (40 first visits). We highlight a prevalence of moderated or advanced kidney disease, in contrast with the literature, which is probably the result of a transversal II level clinic with different specialists involved. Furthermore, in patients with a prolonged follow-up, we observed a progressive better attention to every kidney involvement, particularly in patients in active cancer therapy, by the oncologist colleagues. We observed a reduction of treatment withdrawals due to kidney toxicity, thanks to a multidisciplinary approach and experienced-based management. On the other side, we highlight also a delayed addressing of patients with acute kidney injury (AKI), which often results in chronic kidney damage. This could be related to a delayed identification of the reduced renal function, which is difficult to correctly value in patients with cancer.

Deterioration of Kidney Function Is Affected by Central Arterial Stiffness in Late Life

Cardiovascular diseases affect kidney function. The aim of this study was to investigate the possible associations between hemodynamic parameters and change in kidney function in individuals aged 75 years and older. Data on hemodynamics and blood and urine samples were collected at baseline and during one-year visits. Hemodynamics were split into two groups based on median values. Changes in the estimated glomerular filtration rate (eGFR) were investigated between low and high groups for each hemodynamic parameter using analysis of variance. Changes in the albumin-creatinine ratio (ACR) were examined as binary outcomes (large increase vs. stable) using logistic regression. The population consisted of 252 participants. Participants in the high central systolic blood pressure (cSBP) group had a greater decline in eGFR than participants in the low cSBP group (-6.3% vs. -2.7%, p = 0.006). Participants in the high aortic pulse wave velocity (aPWV) group had a greater decline in eGFR than those in the low aPWV group (-6.8% vs. -2.5%, p = 0.001). Other hemodynamic parameters were not associated with eGFR changes. Hemodynamics were not associated with changes in the ACR; aPWV and cSBP appear to be predictors for eGFR decline in older age; monitoring and treatment of elevated stiffness might be helpful in order to prevent kidney function decline.

Impact of Omicron variant infection on the liver, kidney, and coagulation system in patients undergoing elective surgery: a retrospective case-control study

Purpose: We aimed to investigate the impact of Omicron variant infection on the perioperative organ function in patients undergoing elective surgery. Methods: A total of 5029 patients who underwent elective surgery between October 2022 and January 2023 at our hospital were enrolled. Among them, the patients who underwent elective surgery between October 2022 and November 2022 composed Group 1 (not infected with the Omicron variant) the control group; those who underwent elective surgery between December 2022 and January 2023 composed Group 2 (one month after Omicron variant infection) the experimental group. We further divided the patients into two subgroups for analysis: the tumor subgroup and the nontumor subgroup. Data on organ system function indicators, including coagulation parameters, liver function, complete blood count (CBC), and kidney function, were collected before and after surgery. Differences between the two groups were subsequently analyzed via binary logistic regression analysis. Results: Compared with those in the uninfected patient group, the following changes were observed in patients with Omicron variant infection who underwent elective surgery one month after infection: prothrombin activity (PTa), prothrombin time (PT), fibrinogen, albumin/globulin, alanine aminotransferase (ALT), mean corpuscular hemoglobin concentration (MCHC), platelet (PLT), and anemia were increased AST/ALT, indirect bilirubin (IBILI), eosinophils, and uric acid were decreased before surgery; and lung infection/pneumonia and fibrinogen were increased, while AST/ALT, globulin, total bilirubin (TBIL), white blood cell count (WBC), and uric acid were decreased after surgery. There was no significant difference in the mortality rate or length of hospital stay (LOS) between the two groups. Subgroup analysis revealed elevated monocyte, PLT, and fibrinogen classification, levels and decreased globulin, prealbumin (PBA), eosinophil, and uric acid levels in the tumor subgroup of patients who underwent elective surgery one month after Omicron infection compared with those in the uninfected patients. Compared with the nontumor subgroup, fibrinogen levels, lung infection/pneumonia, TBIL, and PLT count were increased in the uninfected patients, while the globulin and eosinophil levels were decreased. Conclusion: Compared with uninfected patients, patients who underwent elective surgery one month after Omicron variant infection exhibited minimal changes in perioperative coagulation parameters, liver function, CBC counts, and kidney function. Additionally, no significant differences in postoperative mortality or LOS were observed between the two groups.

Trajectories of Kidney Function in Heart Failure Over a 15-Year Follow-Up: Clinical Profiling and Mortality

BACKGROUND

Limited data are available on the long-term trajectory of estimated glomerular filtration rate (eGFR) in patients with chronic heart failure.

OBJECTIVES

The authors evaluated eGFR dynamics using the 2009 Chronic Kidney Disease Epidemiology Collaboration equation and its prognostic significance in a real-world cohort over a 15-year follow-up.

METHODS

A prospective observational registry of ambulatory heart failure outpatients was conducted, with regular eGFR assessments at baseline and on a 3-month schedule for ≤15 years. Urgent kidney function assessments were excluded. Locally weighted error sum of squares curves were plotted for predefined subgroups. Multivariable longitudinal Cox regression analyses were conducted to assess associations with all-cause and cardiovascular death.

RESULTS

A total of 2,672 patients were enrolled consecutively between August 2001 and December 2021. The average age was 66.8 ± 12.6 years, and 69.8% were men. Among 40,970 creatinine measurements, 28,634 were used for eGFR analysis, averaging 10.7 ± 8.5 per patient. Over the study period, a significant decline in eGFR was observed in the entire cohort, with a slope of -1.70 mL/min/1.73 m2 per year (95% CI: -1.75 to -1.66 mL/min/1.73 m2 per year). Older patients, those with diabetes, a preserved ejection fraction, a higher baseline eGFR, elevated hospitalization rates, and those who died during follow-up experienced more pronounced decreases in the eGFR. Moreover, the decrease in kidney function correlated independently with all-cause mortality and cardiovascular death.

CONCLUSIONS

These findings highlight the sustained decline in eGFR over 15 years in patients with heart failure, with variations based on clinical characteristics, and emphasize the importance of regular eGFR monitoring in this population.

Assessment of the 2023 European Kidney Function Consortium (EKFC) equations in a Chinese adult population

OBJECTIVES

The European Kidney Function Consortium (EKFC) developed two novel equations in 2023 for estimating glomerular filtration rate (GFR): one sex-free cystatin C-based equation (EKFCCys) and one creatinine-cystatin C combined equation (EKFCCr-Cys). This study compared their performance with the previous creatinine-based EKFC equation (EKFCCr) and commonly used Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and Berlin Initiative Study (BIS) equations in Chinese adults.

METHODS

A total of 2,438 Chinese adults (mean age=53.04 years) who underwent the 99mTc-DTPA renal dynamic imaging for reference GFR (rGFR) were included. Diagnostic value was evaluated using correlation coefficients, sensitivity, specificity, and area under the receiver operating characteristic curve (ROCAUC). Performance was assessed in terms of bias, precision (interquartile range of the median difference [IQR]), accuracy (percentage of estimates ±30 % of rGFR [P30], and root-mean-square error [RMSE]) across age, sex, and rGFR subgroups. Gender differences in bias and P30 were also analyzed.

RESULTS

Average rGFR was 73.37 mL/min/1.73 m2. EKFC equations showed stronger correlations and larger AUCs compared to the parallel CKD-EPI equations, with EKFCCr-Cys demonstrating the greatest improvement (R=0.771, ROCAUC=0.913). Concerning bias, precision, and accuracy, EKFC equations consistently outperformed CKD-EPI equations. EKFCCr-Cys and EKFCCr performed acceptably well in the entire population and were equivalent to BIS equations in the elderly. All equations, including EKFCCys, showed similar P30 accuracy across sexes.

CONCLUSIONS

EKFC equations provided a reasonable alternative for estimating GFR in the Chinese adult population. While EKFCCys did not outperform EKFCCr, EKFCCr-Cys improved the accuracy of single-marker equations.

Creatinine-Based Definition of Kidney Disease in the Charlson Comorbidity Index May Underestimate Prognosis in Males Compared to an Estimated Glomerular Filtration Rate Definition

(1) Background: The Charlson comorbidity index allocates two points for chronic kidney disease (CKD) if serum creatinine is above 3.0 mg/dL (270 µmol/L). However, contemporary CKD staging is based on the estimated glomerular filtration rate (eGFR) derived from population-based equations. The aim of this study was to determine the correlation between eGFR and the creatinine threshold of the Charlson comorbidity index for defining CKD. (2) Methods: We conducted a cross-sectional study of 664 patients with established CKD attending general nephrology clinics over 6 months. Dialysis patients and kidney transplant recipients were excluded. (3) Results: The median age was 68 years, and 58% of the participants were male. By modeling with fractional polynomial regression, we estimated that a creatinine of 270 µmol/L corresponded with an eGFR of 14.8 mL/min/1.73 m2 for females and 19.4 mL/min/m2 for males. We also estimated that an eGFR of 15 mL/min/1.73 m2 (threshold which defines Stage 5 CKD) corresponded to a serum creatinine of 275 µmol/L for females and 342 µmol/L for males. After applying these sex-specific creatinine thresholds, 39% of males and 3% of females in our CKD study population who scored points for CKD in the Charlson comorbidity index had not yet reached Stage 5 CKD. (4) Conclusions: There is a significant difference in the creatinine threshold to define Stage 5 CKD between males and females, with a bias for greater allocation of Charlson index points for CKD to males despite similar eGFR levels between the sexes. Further research could examine if replacing creatinine with eGFR improves the performance of the Charlson comorbidity index as a prognostic tool.

Aortic Stiffness Can be Predicted From Different eGFR Formulas With Long Follow-Up in the Malmö Diet Cancer Study

We studied the impact of estimated glomerular filtration rate (eGFR) based on either creatinine or cystatin C, or in combination, on vascular aging (aortic stiffness) and central hemodynamics (central systolic blood pressure) in a Swedish urban population with median 17 years of follow-up. Participants (n = 5049) from the population-based Malmö Diet and Cancer Study that underwent baseline examination and later participated in the prospective cardiovascular arm were selected. Of these, 2064 with measured carotid-femoral pulse wave velocity (cfPWV) and central blood pressure at follow-up were enrolled. eGFR was calculated using cystatin C (eGFRCYS) and creatinine (eGFRCR) equations: Caucasian, Asian, pediatric, and adult cohorts (CAPA), the Lund-Malmö revised (LMrev), and the European Kidney Function Consortium (EKFC) equations. Lower adjusted eGFRCR, but not eGFRCYS, were independently associated with higher cfPWV (P < .001, respectively). eGFR <60 mL/min/1.73 m2 determined higher cfPWV except when using the EKFC equation. Conversely, CAPA/LMrev and CAPA/EKFC ratios were not associated with aortic stiffness. Lower eGFRCR is associated with higher future aortic stiffness independently of age, sex, heart rate, mean blood pressure, body mass index, and antihypertensive treatment. The ratio of eGFRCYS and eGFRCR equations could not predict aortic stiffness at all.

Noninvasive Advanced Cardiovascular Magnetic Resonance-Derived Fontan Hemodynamics Are Associated With Reduced Kidney Function But Not Albuminuria

BACKGROUND

Kidney disease is the most important predictor of death in patients with a Fontan circulation, yet its clinical and hemodynamic correlates have not been well established.

METHODS AND RESULTS

A total of 53 ambulatory patients with a Fontan circulation (median age, 16.2 years, 52.8% male patients) underwent advanced cardiovascular magnetic resonance assessment, including 4-dimensional flow imaging and computational fluid dynamics. Estimated glomerular filtration rate (eGFR) <90 mL/min per 1.73 m2 was observed in 20.8% and albumin-to-creatinine ratio >3 mg/mmol in 39.6%. The average eGFR decline rate was -1.83 mL/min per 1.73 m2 per year (95% CI, -2.67 to -0.99; P<0.001). Lower eGFR was associated with older age, larger body surface area at examination, longer time since Fontan procedure, and lower systemic ventricular ejection fraction. Higher albumin-to-creatinine ratio was associated with absence of fenestration at the Fontan operation, and older age and lower systemic ventricular ejection fraction at the assessment. Lower cross-sectional area of the Fontan conduit indexed to flow (r=0.32, P=0.038), higher inferior vena cava-conduit velocity mismatch factor (r=-0.35, P=0.022), higher kinetic energy indexed to flow in the total cavopulmonary connection (r=-0.59, P=0.005), and higher total cavopulmonary connection resistance (r=-0.42, P=0.005 at rest; r=-0.43, P=0.004 during exercise) were all associated with lower eGFR but not with albuminuria.

CONCLUSIONS

Kidney dysfunction and albuminuria are common among clinically well adolescents and young adults with a Fontan circulation. Advanced cardiovascular magnetic resonance-derived metrics indicative of declining Fontan hemodynamics are associated with eGFR and might serve as targets to improve kidney health. Albuminuria might be driven by other factors that need further investigation.

Risk Factors for COVID-19 Infection in Adult Patients: A Retrospective Observational Study in Japan

Purpose

The aim of the study was to identify the characteristics of patients infected with coronavirus disease 2019 (COVID-19) and to determine risk factors for COVID-19 infection in Japanese patients.

Patients and Methods

We conducted a single-center retrospective observational study in Japanese adult patients (≥20 years) who visited Kenwakai Hospital (Nagano Japan). We analyzed data of 378 patients (mean age, 75 ± 14 years; men, 54%) from the hospital's electronic information system. COVID-19 was diagnosed by polymerase-chain reaction. Patients were divided into 2 groups based on diagnosis of COVID-19.

Results

Patients infected with COVID-19 showed significantly higher rates of men (69.8 vs 51.6%, P = 0.025) than uninfected control patients. After adjustment for possible confounding factors, COVID-19 infection was significantly associated with BUN (odds ratio [OR], 1.02; 95% confidence interval [CI], 1.01-1.03) and serum creatinine (Scr) (OR, 1.14; 95% CI, 1.05-1.24). This association was observed in men (BUN, P = 0.012; Scr, P = 0.012), but not in women (BUN, P = 0.43; Scr, P = 0.54).

Conclusion

BUN and Scr are potential risk factors for infection of COVID-19 in Japanese patients, particularly in men. Our results suggest that renal parameters might be important in Japanese male patients for the early detection of COVID-19 infection.

Sleep Duration and Kidney Function - Does Weekend Sleep Matter?

Objective

Weekend sleep duration is linked to health issues, including mortality. However, how weekend sleep duration can impact chronic kidney disease (CKD) still needs to be understood. Therefore, we aimed to analyze how weekend sleep duration is associated with kidney function.

Methods

This is a cross-sectional study. Data were obtained from the 2017-2018 National Health and Nutrition Examination Survey. We included 5362 study participants and categorized them into nine subgroups by sleep duration (short: ≤6 hours, normal: 6-9 hours, and long: ≥9 hours) on weekdays and weekends and analyzed for the respective association with renal function using stratified multivariable linear regression.

Results

Weekend sleep duration for 9 hours or more was associated with decreasing estimated glomerular filtration rate (eGFR) levels by 2.8 to 6.4 mL/min/1.73 m2 among people with long to short weekday sleep duration compared with short weekday and weekend sleep durations (control group) after adjusting for demographic characteristics, body measurement, sleep quality, smoking, and comorbidities. The study population with short weekday sleep duration (sWK) and long weekend sleep duration (lWD) had the most significant decline in eGFR. For the study population with sWK, eGFR level significantly decreased by 1.1 mL/min/1.73 m2 as sleep duration on weekends increased by one hour.

Conclusion

The underlying mediators of lWD and CKD could be the dysregulation of human behaviors, metabolism, or biological functions. Longer weekend sleep duration was linked to a decrease in eGFR levels. It warrants further study to clarify the mediators.

Clinical and biochemical associations of urinary metabolites: quantitative epidemiological approach on renal-cardiometabolic biomarkers

BACKGROUND

Urinary metabolomics has demonstrated considerable potential to assess kidney function and its metabolic corollaries in health and disease. However, applications in epidemiology remain sparse due to technical challenges.

METHODS

We added 17 metabolites to an open-access urinary nuclear magnetic resonance metabolomics platform, extending the panel to 61 metabolites (n = 994). We also introduced automated quantification for 11 metabolites, extending the panel to 12 metabolites (+creatinine). Epidemiological associations between these 12 metabolites and 49 clinical measures were studied in three independent cohorts (up to 5989 participants). Detailed regression analyses with various confounding factors are presented for body mass index (BMI) and smoking.

RESULTS

Sex-specific population reference concentrations and distributions are provided for 61 urinary metabolites (419 men and 575 women), together with methodological intra-assay metabolite variations as well as the biological intra-individual and epidemiological population variations. For the 12 metabolites, 362 associations were found. These are mostly novel and reflect potential molecular proxies to estimate kidney function, as the associations cannot be simply explained by estimated glomerular filtration rate. Unspecific renal excretion results in leakage of amino acids (and glucose) to urine in all individuals. Seven urinary metabolites associated with smoking, providing questionnaire-independent proxy measures of smoking status in epidemiological studies. Common confounders did not affect metabolite associations with smoking, but insulin had a clear effect on most associations with BMI, including strong effects on 2-hydroxyisobutyrate, valine, alanine, trigonelline and hippurate.

CONCLUSIONS

Urinary metabolomics provides new insight on kidney function and related biomarkers on the renal-cardiometabolic system, supporting large-scale applications in epidemiology.

Plausible prediction of renoprotective effects of sodium-glucose cotransporter-2 inhibitors in patients with chronic kidney diseases

This narrative review was conducted due to uncertainty in predicting the beneficial impact of sodium-glucose cotransporter-2 (SGLT2) inhibitors on a dip of estimated glomerular filtration rate (eGFR), regardless of albuminuria presence, with the aim of elucidating plausible predictors of kidney function outcome among patients treated with SGLT2 inhibitors. The PubMed and Web of Science databases were searched in May 2023 for relevant articles published in English between 2013 and 2023. A total of 25 full-length scientific publications (comprising 11 large randomized trials and two cohort studies) were included for analysis. The majority of studies demonstrated a limited value of conventional biomarkers, such as initial decline in eGFR, a trajectory of eGFR during SGLT2 inhibitor administration, and urine albumin-to-creatinine ratio (UACR), in prediction of renoprotection. Included studies showed that the tendency to decreased eGFR, UACR, hemoglobin, glycosylated hemoglobin, lipid profile, serum uric acid, inflammatory biomarkers and natriuretic peptides did not predict clinical outcomes in groups without heart failure (HF) treated with SGLT2 inhibitors. In HF groups, biomarkers of inflammation, kidney injury, oxidative stress, mitochondrial dysfunction, ketogenesis, energy metabolism, and adipose tissue dysfunction (adropin and irisin), were detected with the aim of finding potential biomarkers. Biomarkers of adipose tissue dysfunction and inflammation may be promising for predicting SGLT2 inhibitor benefit compared with N-terminal pro-B-type natriuretic peptide and energy metabolism indicators.

Real-time estimation of nephron activity with a linear measurement system (RENAL-MS) predicts postoperative estimated glomerular filtration rate

OBJECTIVE

To determine whether a simple point-of-care measurement system estimating renal parenchymal volume using tools ubiquitously available could be used to replace nuclear medicine renal scintigraphy (NMRS) in current clinical practice to predict estimated glomerular filtration rate (eGFR) after nephrectomy by estimating preoperative split renal function.

PATIENTS AND METHODS

We performed a retrospective review of patients who underwent abdominal cross-sectional imaging (computed tomography/magnetic resonance imaging) and mercaptoacetyltriglycine (MAG3) NMRS prior to total nephrectomy at a single institution. We developed the real-time estimation of nephron activity with a linear measurement system (RENAL-MS) method of estimating postoperative renal function via the following technique: renal parenchymal volume of the removed kidney relative to the remaining kidney was estimated as the product of renal length and the average of six renal parenchymal thickness measurements. The utility of this value was compared to the utility of the split renal function measured by MAG3 for prediction of eGFR and new onset Stage 3 chronic kidney disease (CKD) at ≥90 days after nephrectomy using uni- and multivariate linear and logistic regression.

RESULTS

A total of 57 patients met the study criteria. The median (interquartile range [IQR]) age was 69 (61-80) years. The median (IQR) pre- and postoperative eGFR was 74 (IQR 58-90) and 46 (35-62) mL/min/1.73 m2 , respectively. [Correction added on 29 December 2023, after first online publication: The data numbers in the preceding sentence have been corrected.] Correlations between actual and predicted postoperative eGFR were similar whether the RENAL-MS or NMRS methods were used, with correlation using RENAL-MS being slightly numerically but not statistically superior (R = 0.82 and 0.76; P = 0.138). Receiver operating characteristic curve analysis using logistic regression estimates incorporating age, sex, and preoperative creatinine to predict postoperative Stage 3 CKD were similar between RENAL-MS and NMRS (area under the curve 0.93 vs. 0.97). [Correction added on 29 December 2023, after first online publication: The data numbers in the preceding sentence have been corrected.] CONCLUSION: A point-of-care tool to estimate renal parenchymal volume (RENAL-MS) performed equally as well as NMRS to predict postoperative eGFR and de novo Stage 3 CKD after nephrectomy in our population, suggesting NMRS may not be necessary in this setting.

Kidney Increase Natriuresis but Not Glomerular Filtration Under Veno-venous ECMO, a Retrospective Study

PURPOSE

Acute kidney injury is a frequent complication of acute respiratory distress syndrome (ARDS). We aim to study the evolution of kidney function in patients presenting severe ARDS and requiring veno-venous extracorporeal membrane oxygenation (VV ECMO).

METHODS

We conducted a multicenter retrospective study, including adult patients requiring VV ECMO for ARDS. The primary outcome was the evolution of the serum creatinine level after VV ECMO initiation. Secondary outcomes were change in urine output, and urine biochemical parameters after VV ECMO initiation.

RESULTS

One hundred and two patients were included. VV ECMO was initiated after a median of 6 days of mechanical ventilation, mainly for ARDS caused by COVID-19 (73%). Serum creatinine level did not significantly differ after VV ECMO initiation (P = .20). VV ECMO was associated with a significant increase in daily urine output (+6.6 mL/kg/day, [3.8;9.3] P < .001), even after adjustment for potential confounding factors; with an increase in natriuresis. The increase in urine output under VV ECMO was associated with a reduced risk of receiving kidney replacement therapy (OR 0.4 [0.2;0.8], P = .026).

CONCLUSIONS

VV ECMO initiation in severe ARDS is associated with an increase in daily urine output and natriuresis, without change in glomerular filtration rate.

Evaluation of Gabapentin and Pregabalin Use in Hospitalized Patients With Decreased Kidney Function

Background: Gabapentin and pregabalin are well-tolerated medications primarily cleared by the kidney. Patients receiving higher gabapentinoid doses with decreased kidney function may be at an increased risk of adverse effects (AEs), but limited evidence exists evaluating gabapentinoid dosing and AEs in this population. Objective: To determine whether patients with decreased creatinine clearance (CrCl) experienced increased frequency of AEs related to gabapentinoid dose at hospital admission. Methods: Single-center retrospective cohort study in adults with a gabapentinoid prescription and serum creatinine measurement documented on hospital admission. The primary outcome was the appropriateness of gabapentinoid prescription based on CrCl (stratified by CrCl ≥60 mL/min, <60 mL/min, 15-29 mL/min, and <15 mL/min) at admission. Secondary outcomes included the incidence of AEs related to gabapentinoids and concomitant opioid and psychiatric prescriptions. Results: A total of 286 patients were included in this study (gabapentin n = 234, pregabalin n = 52). Patients with a CrCl <60 mL/min and doses above the manufacturer's recommendation were prescribed gabapentin (34%) and pregabalin (22.7%). For patients with a CrCl of 15 to 29 mL/min and <15 mL/min groups, inappropriately high doses were prescribed for gabapentin (48.8%) and pregabalin (45%). A significant increase in recorded falls (P = 0.029) was identified in patients with a CrCl <60 mL/min. Concomitant opioid and psychiatric medications contributed to a higher prevalence of AEs regardless of CrCl. Conclusions: Patients with a CrCl <60 mL/min were frequently prescribed inappropriately high doses of gabapentinoids. The relationship between gabapentinoid dosing, kidney function, and the incidence of gabapentinoid-related AEs at hospital admission requires larger, multicentre studies.

Urinary Vitamin D Binding Protein: A Marker of Kidney Tubular Dysfunction in Patients at Risk for Type 2 Diabetes

Context

Recent studies have reported elevated urinary vitamin D binding protein (uVDBP) concentrations in patients with diabetic kidney disease, although the utility of uVDBP to predict deterioration of kidney function over time has not been examined.

Objective

Our objective was to assess the association of uVDBP with longitudinal changes in kidney function.

Methods

Adults at-risk for type 2 diabetes from the Prospective Metabolism and Islet Cell Evaluation (PROMISE) study had 3 assessments over 6 years (n = 727). Urinary albumin-to-creatinine ratio (ACR) and estimated glomerular filtration rate (eGFR) were used as measures of kidney function. Measurements of uVDBP were performed with enzyme-linked immunosorbent assay and normalized to urine creatinine (uVDBP:cr). Generalized estimating equations (GEEs) evaluated longitudinal associations of uVDBP and uVDBP:cr with measures of kidney function, adjusting for covariates.

Results

Renal uVDBP loss increased with ACR severity at baseline. Individuals with normoalbuminuria, microalbuminuria, and macroalbuminuria had median log uVDBP:cr concentrations of 1.62 μg/mmol, 2.63 μg/mmol, and 2.48 μg/mmol, respectively, and ACR positively correlated with uVDBP concentrations (r = 0.37; P < .001). There was no significant association between uVDBP and eGFR at baseline. Adjusted longitudinal GEE models indicated that each SD increase both in baseline and longitudinal uVDBP:cr was significantly associated with higher ACR over 6 years (β = 30.67 and β = 32.91, respectively). Conversely, neither baseline nor longitudinal uVDBP:cr measures showed a significant association with changes in eGFR over time. These results suggest that loss of uVDBP:cr over time may be a useful marker for predicting renal tubular damage in individuals at risk for diabetes.

Genome-wide study investigating effector genes and polygenic prediction for kidney function in persons with ancestry from Africa and the Americas

Chronic kidney disease is a leading cause of death and disability globally and impacts individuals of African ancestry (AFR) or with ancestry in the Americas (AMS) who are under-represented in genome-wide association studies (GWASs) of kidney function. To address this bias, we conducted a large meta-analysis of GWASs of estimated glomerular filtration rate (eGFR) in 145,732 AFR and AMS individuals. We identified 41 loci at genome-wide significance (p < 5 × 10-8), of which two have not been previously reported in any ancestry group. We integrated fine-mapped loci with epigenomic and transcriptomic resources to highlight potential effector genes relevant to kidney physiology and disease, and reveal key regulatory elements and pathways involved in renal function and development. We demonstrate the varying but increased predictive power offered by a multi-ancestry polygenic score for eGFR and highlight the importance of population diversity in GWASs and multi-omics resources to enhance opportunities for clinical translation for all.

Circulating metabolites associated with kidney function decline and incident CKD: a multi-platform population-based study

Background

Investigation of circulating metabolites associated with kidney function and chronic kidney disease (CKD) risk could enhance our understanding of underlying pathways and identify new biomarkers for kidney function.

Methods

We selected participants from the population-based Rotterdam Study with data on circulating metabolites and estimated glomerular filtration rate based on serum creatinine (eGFRcreat) available at the same time point. Data on eGFR based on serum cystatin C (eGFRcys) and urine albumin-to-creatinine ratio (ACR) were also included. CKD was defined as eGFRcreat <60 ml/min per 1.73 m2. Data on circulating metabolites (ntotal = 1381) was obtained from the Nightingale and Metabolon platform. Linear regression, linear mixed, and Cox proportional-hazards regression analyses were conducted to study the associations between metabolites and kidney function. We performed bidirectional two-sample Mendelian randomization analyses to investigate causality of the identified associations.

Results

We included 3337 and 1540 participants with data from Nightingale and Metabolon, respectively. A total of 1381 metabolites (243 from Nightingale and 1138 from Metabolon) were included in the analyses. A large number of metabolites were significantly associated with eGFRcreat, eGFRcys, ACR, and CKD, including 16 metabolites that were associated with all four outcomes. Among these, C-glycosyltryptophan (HR 1.50, 95%CI 1.31;1.71) and X-12026 (HR 1.46, 95%CI 1.26;1.68) were most strongly associated with CKD risk. We revealed sex differences in the associations of 11-ketoetiocholanolone glucuronide and 11-beta-glucuronide with the kidney function assessments. No causal associations between the identified metabolites and kidney function were observed.

Conclusion

Our study indicates that several circulating metabolites are associated with kidney function which are likely to have potential as biomarkers, rather than as molecules involved in the pathophysiology of kidney function decline.

Physical activity, chronic kidney disease, and cardiovascular risk: A study in half a million adults

OBJECTIVE

There is a growing prevalence of chronic kidney disease (CKD), a condition associated with a higher cardiovascular disease (CVD) risk. We assessed the association between self-reported physical activity (PA) and CKD and also studied whether PA attenuates CKD-associated CVD risk.

METHODS

A cohort of Spanish adults (18-64 years) participated in this nationwide study. Participants were categorized at baseline as being either inactive (performing no PA), regularly, or insufficiently active (meeting or not, respectively, international PA recommendations) and were followed for up to 5 years. The presence of CKD (estimated glomerular filtration rate <60 mL/min/1.73 m2 ) and major CVD risk factors (diabetes, hypercholesterolemia, hypertension, obesity) was determined at baseline and at follow-up.

RESULTS

517 917 participants (44 ± 9 years, 67% male, CKD prevalence = 7%) were studied at baseline, with prospective analyses (median follow-up = 2 years, range = 2-5) in a subcohort of 264 581 individuals. Compared to physical inactivity, cross-sectional analyses at baseline showed that regular PA (odds ratio = 0.80; 95% confidence interval = 0.79-0.81), but not insufficient PA (1.02; 0.99-1.04) was associated with lower CKD prevalence. However, prospective analyses failed to confirm this association (p > 0.1). In turn, CKD was associated with a higher prevalence of hypertension (+3%) and diabetes (+5%) at baseline and with a greater incidence of hypertension at follow-up (+37%). Among those participants with CKD, regular PA was associated with a lower prevalence (-45% to -7%) and incidence (-38% to -4%) of all CVD risk factors.

CONCLUSION

Although PA might not reduce incident CKD in the middle term (~2 years), it can attenuate the CVD risk linked to this condition.

Cross-sectional analysis of healthy individuals across decades: Aging signatures across multiple physiological compartments

The study of age-related biomarkers from different biofluids and tissues within the same individual might provide a more comprehensive understanding of age-related changes within and between compartments as these changes are likely highly interconnected. Understanding age-related differences by compartments may shed light on the mechanism of their reciprocal interactions, which may contribute to the phenotypic manifestations of aging. To study such possible interactions, we carried out a targeted metabolomic analysis of plasma, skeletal muscle, and urine collected from healthy participants, age 22-92 years, and identified 92, 34, and 35 age-associated metabolites, respectively. The metabolic pathways that were identified across compartments included inflammation and cellular senescence, microbial metabolism, mitochondrial health, sphingolipid metabolism, lysosomal membrane permeabilization, vascular aging, and kidney function.

Comparison of different estimated glomerular filtration rates for monitoring of kidney function in oncology patients

Background

Tyrosine kinase inhibitors (TKIs) are associated with kidney function deterioration. A shift is ongoing towards glomerular filtration rate (GFR) equations based on other protein markers, such as cystatin C (CSTC) and β-trace protein (BTP). We evaluated various GFR equations for monitoring of kidney function in actively treated oncology patients.

Methods

We monitored 110 patients receiving a TKI. Blood and urine were collected during therapy. Serum analysis included creatinine (Cr), CSTC and BTP; for consequent GFR determination. Urine was analysed for protein, albumin, immunoglobulin G, and α-1-microglobulin. A similar analysis was done in a patient subgroup receiving immune checkpoint inhibitors (ICI) as prior or subsequent line of therapy.

Results

Cr remained constant during TKI treatment (P = 0.7753), whereas a significant decrease in CSTC (from week 2 onward, P < 0.0001) and BTP (at weeks 2 and 4, P = 0.0100) were noticed. Consequently, GFR estimations, using CSTC and/or BTP as a biochemical parameter, showed an apparent increase in GFR, whereas this was not observed for Cr-related GFR estimations. As a result, the GFR gap (ΔGFR) was significantly different from week 2 onward between Cr-based and CSTC-based GFR and between BTP-based and CSTC-based GFR. Glomerular damage was noticed with significant increase in urine protein-to-creatinine ratio, albumin-to-creatinine ratio and immunoglobulin G (all P < 0.0001). No change in α-1-microglobulin was seen. ICI treatment had no effect on Cr (P = 0.2262), CSTC (P = 0.7341), and BTP concentrations (P = 0.3592).

Conclusion

GFR equations, in which CSTC is incorporated, fail to correctly estimate the GFR in oncology patients treated with TKIs. As TKI-treated patients show clear signs of glomerular injury, further assessment is needed on how to correctly monitor the kidney function in actively treated oncology patients.

The effect of green tea (Camellia sinensis) on lipid profiles and renal function in people with type 2 diabetes and nephropathy: a randomized controlled clinical trial

Introduction

Diabetic nephropathy is one of the most important microvascular complications of diabetes. Despite the modern treatments, herbs or medicinal plants have gained wide attention. One of these herbs is green tea (Camellia sinensis), which may have an impact on renal function, lipid profiles, and HbA1c. However, the evidence for this is unclear and limited. The present study aimed to evaluate the effect of different doses of green tea on these parameters in type 2 diabetes patients (T2DM) with nephropathy.

Methods

Sixty-six individuals with T2DM nephropathy (aged 30-70 years) were randomly assigned to receive three cups of green tea/day (n = 22), two cups of green tea/day (n = 22), and the control group (n = 22) for 12 weeks. Lipid profiles, glycated hemoglobin A1c (HbA1c), and renal markers were measured before and after intervention. Data were analyzed using SPSS software version 23. One-way analysis of variance (ANOVA), least significant difference (LSD) post hoc, and analysis of covariance were used to compare quantitative variables.

Results

In total, 64 participants completed the study. Consuming three cups of infusion green tea per day (7.5 gr) led to a significant reduction in serum levels of total cholesterol (p = 0.009) and HbA1c (p = 0.006) and increased in high-density lipoprotein cholesterol (HDL-C) (p = 0.02) compared with the control group who did not drink green tea. However, no significant differences were observed for other variables.

Conclusion

In general, it was found that drinking three cups of green tea infusion (7.5 gr) per day produced beneficial effects on some lipid profiles and HbA1c without any adverse effects on renal function in patients with T2DM nephropathy. More studies are needed to fully elucidate these findings.

Clinical trial registration

Iranian Registry of Clinical Trials (www.irct.ir) under registry number: IRCT2014020114538N2.

Recommended Methods of Drug Dosing Adjustment for Patients With Renal Impairment

Since 2020, there have been changes in Food and Drug Administration guidance and in recommendations by national organizations with a focus on kidney diseases pertaining to the choice of equations used to estimate creatinine clearance and glomerular filtration rate in patients with renal impairment. This includes a recommendation by the National Kidney Foundation to avoid the use of the Cockcroft-Gault equation for drug dosing in patients with renal impairment. This commentary provides an overview of recent recommendations concerning kidney function assessment that have important implications for drug dosing in patients with renal impairment and provides suggestions for implementing these recommendations.

Kidney functional reserve and damage biomarkers in subclinical chronic kidney disease and acute kidney injury

Significant loss of kidney function is not easily identified by serum creatinine (sCr)-based measurements. In the presence of normal sCr, decreased kidney functional reserve (KFR) may identify a significant loss of function. We evaluated KFR in experimental subclinical chronic kidney disease (sCKD) before and after brief ischemia-reperfusion injury (IRI). Using fluorescein isothiocyanate-labeled sinistrin, glomerular filtration rate (GFR) was measured transcutaneously before and after adenine-induced sCKD, and 1 and 2 wk after brief IRI, and compared with urinary kidney damage biomarkers. sCKD reduced stimulated and unstimulated GFR by ∼20% while reducing KFR by 50%. IRI reduced unstimulated GFR for 14 days, but KFR remained relatively unchanged in sCKD and transiently increased in control kidneys at 7 days. sCr increased and creatinine clearance (CrCl) decreased only immediately after IRI; sCr and CrCl correlated poorly with measured GFR except on day 1 after IRI. Heterogeneity in sCr and CrCl resulted from variation in tubular creatinine secretion. The increase in damage biomarker concentrations persisted for up to 14 days after IRI, allowing retrospective detection of sCKD before AKI by urine clusterin/urine kidney injury molecule-1 with an area under the curve of 1.0. sCr and CrCl are unreliable unless sCr is acutely elevated. Measurement of KFR and urine damage biomarker excretion detected sCKD despite normal sCr and CrCl. After IRI, the urine clusterin-to-urine kidney injury molecule-1 ratio may identify prior sCKD.NEW & NOTEWORTHY Early kidney function loss is poorly identified by serum creatinine (sCr)-based measurements. Direct kidney functional reserve (KFR) measurement before kidney injury and elevated urinary biomarkers clusterin and kidney injury molecule-1 detect subclinical chronic kidney disease (sCKD) after kidney injury despite normal range sCr and creatinine clearance. Reliance on sCr masks underlying sCKD. Acute kidney injury risk evaluation requires direct glomerular filtration rate measurement and KFR, whereas kidney damage biomarkers facilitate identification of prior subclinical injury.

Association of linear growth velocities between 0 and 6 years with kidney function and size at 10 years: A birth cohort study in Ethiopia

BACKGROUND

Risk of noncommunicable diseases accrues from fetal life, with early childhood growth having an important role in adult disease risk. There is a need to understand how early-life growth relates to kidney function and size.

OBJECTIVES

This study aimed to assess the association of linear growth velocities among children between 0 and 6 y with kidney function and size among children aged 10 y.

METHODS

The Ethiopian Anthropometric and Body Composition birth cohort recruited infants born at term to mothers living in Jimma with a birth weight of ≥1500 g and without congenital malformations. Participants were followed up with 13 measurements between birth and 6 y of age. The latest follow-up was at ages 7-12 y with measurement of serum cystatin C as a marker of kidney function and ultrasound assessment of kidney dimensions. Kidney volume was computed using an ellipsoid formula. Linear-spline multilevel modeling was used to compute linear growth velocities between 0 and 6 y. Multiple linear regression modeling was used to examine the associations of linear growth velocities in selected age periods with cystatin C and kidney size.

RESULTS

Data were captured from 355 children, at a mean age of 10 (range 7-12) y. The linear growth velocity was high between 0 and 3 mo and then decreased with age. There was no evidence of an association of growth velocity ≤24 mo with cystatin C at 10 y. Between 24 and 48 and 48 and 76 mo, serum cystatin C was higher by 2.3% [95% confidence interval (CI): 0.6, 4.2] and 2.1% (95% CI: 0.3, 4.0) for 1 SD higher linear growth velocity, respectively. We found a positive association between linear growth velocities at all intervals between 0 and 6 y and kidney volume.

CONCLUSIONS

Greater linear growth between 0 and 6 y of development was positively associated with kidney size, and greater growth velocity after 2 y was associated with higher serum cystatin C concentrations.

Laparoscopic to robotic living donor nephrectomy: Is it time to change surgical technique?

BACKGROUND

We aimed to explore differences in outcomes of robotic and laparoscopic donor nephrectomies (LDN).

METHODS

This study compared robotic and laparoscopic surgical techniques for live donor nephrectomies in 153 patients at a single centre.

RESULTS

Left nephrectomies were more common in both groups, but with no significant difference between the groups (76.6% vs. 77.6%, p = 0.88). The robotic donor nephrectomies (RDN) group experienced significantly less blood loss (60 vs. 134 mL, p < 0.01), but warm ischaemia time was similar between groups (3.2 vs. 3.7 min, p = 0.54).The RDN group had decreased subjective pain scores (3.54 vs. 4.21, p = 0.04) and shorter length of hospitalisation (2.22 vs. 3.04 days, p < 0.01).There were also fewer complications in the RDN than the LDN group (4 vs. 8, p = 0.186).

CONCLUSION

This study demonstrated that RDN is a safe and alternative to LDN. Decreased blood loss and hospital stays and fewer complications may reflect decreased tissue manipulation with robotic assistance.

Impact of Proton Pump Inhibitors on Kidney Function and Chronic Kidney Disease Progression: A Systematic Review

Proton pump inhibitors (PPIs) are widely prescribed medications for the management of various gastrointestinal disorders, primarily gastroesophageal reflux disease (GERD) and peptic ulcers. However, recent concerns have emerged regarding their potential adverse effects on kidney function and their role in the progression of chronic kidney disease (CKD). This systematic review aims to comprehensively analyze the existing literature to assess the impact of PPI use on kidney function and CKD progression. We took information from PubMed, PubMed Central (PMC), and Google Scholar articles from the last 10 years, from 2013 to 2023, and looked for links between PPI use and a number of kidney-related outcomes. These included acute kidney injury, a drop in the estimated glomerular filtration rate (eGFR), and new cases of CKD. The findings of this systematic review highlight the need for a thorough evaluation of the benefits and risks associated with PPI use, particularly in patients with pre-existing kidney conditions, in order to inform clinical decision-making and improve were taken out and looked at to see if there were any links between PPI use and different kidney-related events, such as acute kidney injury, a drop in the estimated eGFR, and the development of CKD. The review also explores potential mechanisms underlying PPI-induced nephrotoxicity. The findings of this systematic review highlight the need for a thorough evaluation of the benefits and risks associated with PPI use, particularly in patients with pre-existing kidney conditions, in order to inform clinical decision-making and improve patient care. Further research is warranted to better understand the complex interplay between PPIs, kidney function, and CKD progression.

Protective effects of vitamin D3 (cholecalciferol) on vancomycin-induced oxidative nephrotoxic damage in rats

CONTEXT

Vancomycin (VCM), an important antibiotic against refractory infections, has been used to treat secondary infections in severe COVID-19 patients. Regrettably, VCM treatment has been associated with nephrotoxicity. Vitamin D₃ can prevent nephrotoxicity through its antioxidant effect.

OBJECTIVE

This study tests the antioxidant effect of vitamin D₃ in the prevention of VCM-induced nephrotoxicity.

MATERIALS AND METHODS

Wistar Albino rats (21) were randomly divided into 3 groups: (A) control; (B) VCM 300 mg/kg daily for 1 week; and (C) VCM plus vitamin D₃ 500 IU/kg daily for 2 weeks. All the rats were sacrificed and serum was separated to determine kidney function parameters. Their kidneys were also dissected for histological examination and for oxidative stress markers.

RESULTS

Lipid peroxidation, creatinine, and urea levels decreased significantly (p < 0.0001) in the vitamin D₃-treated group (14.46, 84.11, 36.17%, respectively) compared to the VCM group that was given VCM (MIC<2 μg/mL) only. A significant increase was observed in superoxide dismutase levels in the vitamin D₃-treated group (p < 0.05) compared to rats without treatment. Furthermore, kidney histopathology of the rats treated with vitamin D₃ showed that dilatation, vacuolization and necrosis tubules decreased significantly (p < 0.05) compared with those in the VCM group. Glomerular injury, hyaline dystrophy, and inflammation improved significantly in the vitamin D₃ group (p < 0.001, p < 0.05, p < 0.05, respectively) compared with the VCM group.

DISCUSSION AND CONCLUSIONS

Vitamin D₃ can prevent VCM nephrotoxicity. Therefore, the appropriate dose of this vitamin must be determined, especially for those infected with COVID-19 and receiving VCM, to manage their secondary infections.

The impact of preoperative kidney replacement therapy on kidney outcome and survival in patients with left ventricular assist device

Left ventricular assist device (LVAD) has been highlighted as a new treatment option in the end-stage heart failure (HF). Kidney outcome after LVAD in severe cardiorenal syndrome (CRS) patients requiring kidney replacement therapy (KRT) is unclear. We investigated the impact of preoperative KRT on kidney function and survival in LVAD patients with severe CRS. A total of 50 patients followed up for at least 1 year after LVAD implantation was analyzed. The primary outcomes were estimated glomerular filtration rate and survival rate. Patients were divided into two groups depending on in-hospital KRT before LVAD implantation: the control group (n = 33) and the KRT group (n = 17). Postoperative KRT was performed for 76.5% of patients in the KRT group, and all of them discontinued KRT before discharge. There were no statistically significant differences in the degree of eGFR decline in survivors according to preoperative KRT. Although there were no statistically significant differences in the degree of eGFR decline in survivors regardless of preoperative KRT, old age (β -0.94, p < 0.01), preexisting chronic kidney disease (β -21.89, p < 0.01), and high serum creatinine (β -13.95, p < 0.01) were identified as independent predictors of post-LVAD eGFR decline. Mortality rate was higher, and more patients progressed to end-stage kidney disease in KRT group than control group. However, LVAD still can be considered as the treatment option in end-stage HF patients with severe CRS requiring KRT, especially in those with young age and previous normal kidney function.

The Association between Kidney Function Biomarkers and Delayed Memory Impairments among Older Adults in the European North of Russia

The prevention of memory decline requires better knowledge of biological markers. We studied the associations between kidney function biomarkers and memory decline (assessed with the Mini-Mental State Examination-MMSE) in elderly individuals without dementia (MMSE 24-30, age 60-74 years, n = 643, Arkhangelsk, Russia). Participants were divided by sex and into three groups according to the delayed memory performance: recall of 0-1, 2, and 3 out of 3 words. The median of serum creatinine was 82 μmol/L in men who recalled 2 words and both medians in those recalling 3 and 0-1 words were 87 μmol/L. The 90th percentile for creatinine in men recalling 0-1 words (115.0 μmol/L) exceeded the upper limit of the normal range (110.5 μmol/L), while those who recalled 3 and 2 words had 90th percentiles within the normal range (109 and 101 μmol/L, respectively). Glomerular filtration rates were normal (≥60 mL/min/1.73 m2) with a median of 92.0 mL/min/1.73 m2 in men who recalled 2 words, 84.4 and 84.9 mL/min/1.73 m2 in men who recalled 3 and 0-1 words, respectively. None of these associations were observed in women. A reduced serum creatinine in older non-demented men may indicate the initial stages of memory decline, while the increased creatinine may reflect further stages of memory impairment.

Absence of Coronary Artery Disease is a Strong Negative Predictor of Major Adverse Cardiovascular Events in Patients with Chronic Kidney Disease

Purpose

To investigate the interplay between chronic kidney disease (CKD) and coronary artery disease (CAD) on the incidence of cardiovascular events in patients with suspected chronic coronary syndrome (CCS).

Patients and Methods

Patients with suspected CCS who underwent first-time coronary angiography in Western Denmark between 2003 and 2016 were included in this cohort study. Moreover, an age- and sex-matched general population cohort was established. Patients were stratified according to estimated glomerular filtration rate (eGFR). Presence of CAD was defined as ≥1 obstructive stenosis or non-obstructive diffuse disease. Major adverse cardiovascular events (MACE) were defined as a composite of myocardial infarction, ischemic stroke, and cardiac death.

Results

A total of 42,611 patients were included with a median follow-up of 7.3 years. Patients without and with CAD had MACE rates per 100 person-years that were 0.52 and 1.67 for eGFR ≥90 mL/min/1.73 m2, 0.68 and 2.09 for eGFR 60-89 mL/min/1.73 m2, 1.27 and 3.85 for eGFR 30-59 mL/min/1.73 m2, and 2.27 and 6.92 for eGFR <30 mL/min/1.73 m2. Comparing to eGFR ≥90 mL/min/1.73 m2, the adjusted incidence rate ratios for MACE were 1.29 (1.10-1.51) for eGFR 60-89 mL/min/1.73 m2, 1.86 (1.49-2.33) for eGFR 30-59 mL/min/1.73 m2, and 3.57 (1.92-6.67) for eGFR <30 mL/min/1.73 m2 in patients without CAD, and 1.11 (1.03-1.20), 1.71 (1.55-1.90), and 2.46 (1.96-3.09) in patients with CAD. The inverse relationship between kidney function and risk of MACE was confirmed when comparing patients with and without CAD to matched individuals in the general population.

Conclusion

Absence of CAD is a strong negative predictor of major adverse cardiovascular events in patients with CKD.

Higher beta-hydroxybutyrate ketone levels associated with a slower kidney function decline in ADPKD

BACKGROUND AND HYPOTHESIS

Dysregulated energy metabolism is a recently discovered key feature of Autosomal Dominant Polycystic Kidney Disease (ADPKD). Cystic cells depend on glucose and are poorly able to use other energy sources such as ketone bodies. Raising ketone body concentration reduced disease progression in animal models of polycystic kidney diseases. Therefore, we hypothesized that higher endogenous plasma beta-hydroxybutyrate concentrations are associated with reduced disease progression in patients with ADPKD.

METHODS

We analyzed data from 670 patients with ADPKD participating in the DIPAK cohort, a multi-center prospective observational cohort study. Beta-hydroxybutyrate was measured at baseline using nuclear magnetic resonance spectroscopy. Participants were excluded if they had type 2 diabetes, were using disease-modifying drugs (e.g. tolvaptan, somatostatin analogs), were not fasting, or had missing beta-hydroxybutyrate levels, leaving 521 participants for the analyses. Linear regression analyses were used to study cross-sectional associations and linear mixed-effect modeling for longitudinal associations.

RESULTS

Of the participants, 61% were female, with an age of 47.3 ± 11.8 years, a height-adjusted total kidney volume (htTKV) of 834 (IQR 495-1327) ml/m, and an estimated glomerular filtration rate (eGFR) of 63.3 ± 28.9 mL/min/1.73m2. The median concentration of beta-hydroxybutyrate was 94 (IQR 68-147) µmol/L. Cross-sectionally, beta-hydroxybutyrate was neither associated with eGFR nor with htTKV. Longitudinally, beta-hydroxybutyrate was positively associated with eGFR slope (B = 0.35 ml/min/1.73m2 (95% CI 0.09 to 0.61), p = 0.007), but not with kidney growth. After adjustment for potential confounders, every doubling in beta-hydroxybutyrate concentration was associated with an improvement in the annual rate of eGFR by 0.33 ml/min/1.73m2 (95% CI 0.09 to 0.57, p = 0.008).

CONCLUSION

These observational analyses support the hypothesis that interventions that raise beta-hydroxybutyrate concentration could reduce the rate of kidney function decline in patients with ADPKD.