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Background Many outcomes of high priority to patients and clinicians are infrequently and inconsistently reported across trials in chronic kidney disease (CKD), which generates research waste and limits evidence-informed decision making. We aimed to generate consensus among patients/caregivers and health professionals on critically important outcomes for trials in CKD prior to kidney failure and the need for kidney replacement therapy, and to describe the reasons for their choices. Methods This was an online two-round international Delphi survey. Adult patients with CKD (all stages and diagnoses), caregivers and health professionals who could read English, Spanish or French were eligible. Participants rated the importance of outcomes using a Likert scale (7–9 indicating critical importance) and a Best–Worst Scale. The scores for the two groups were assessed to determine absolute and relative importance. Comments were analysed thematically. Results In total, 1399 participants from 73 countries completed Round 1 of the Delphi survey, including 628 (45%) patients/caregivers and 771 (55%) health professionals. In Round 2, 790 participants (56% response rate) from 63 countries completed the survey including 383 (48%) patients/caregivers and 407 (52%) health professionals. The overall top five outcomes were: kidney function, need for dialysis/transplant, life participation, cardiovascular disease and death. In the final round, patients/caregivers indicated higher scores for most outcomes (17/22 outcomes), and health professionals gave higher priority to mortality, hospitalization and cardiovascular disease (mean difference >0.3). Consensus was based upon the two groups yielding median scores of ≥7 and mean scores >7, and the proportions of both groups rating the outcome as 'critically important' being >50%. Four themes reflected the reasons for their priorities: imminent threat of a health catastrophe, signifying diminishing capacities, ability to self-manage and cope, and tangible and direct consequences. Conclusion Across trials in CKD, the outcomes of highest priority to patients, caregivers and health professionals were kidney function, need for dialysis/transplant, life participation, cardiovascular disease and death. [ABSTRACT FROM AUTHOR]

Background There is interest in identifying novel filtration markers that lead to more accurate GFR estimates than current markers (creatinine and cystatin C) and are more consistent across demographic groups. We hypothesize that large-scale metabolomics can identify serum metabolites that are strongly influenced by glomerular filtration rate (GFR) and are more consistent across demographic variables than creatinine, which would be promising filtration markers for future investigation. Methods We evaluated the consistency of associations between measured GFR (mGFR) and 887 common, known metabolites quantified by an untargeted chromatography- and spectroscopy-based metabolomics platform (Metabolon) performed on frozen blood samples from 580 participants in Chronic Kidney Disease in Children (CKiD), 674 participants in Modification of Diet in Renal Disease (MDRD) Study and 962 participants in African American Study of Kidney Disease and Hypertension (AASK). We evaluated metabolite–mGFR correlation association with metabolite class, molecular weight, assay platform and measurement coefficient of variation (CV). Among metabolites with strong negative correlations with mGFR (r < −0.5), we assessed additional variation by age (height in children), sex, race and body mass index (BMI). Results A total of 561 metabolites (63%) were negatively correlated with mGFR. Correlations with mGFR were highly consistent across study, sex, race and BMI categories (correlation of metabolite–mGFR correlations between 0.88 and 0.95). Amino acids, carbohydrates and nucleotides were more often negatively correlated with mGFR compared with lipids, but there was no association with metabolite molecular weight, liquid chromatography/mass spectrometry platform and measurement CV. Among 114 metabolites with strong negative associations with mGFR (r < −0.5), 27 were consistently not associated with age (height in children), sex or race. Conclusions The majority of metabolite–mGFR correlations were negative and consistent across sex, race, BMI and study. Metabolites with consistent strong negative correlations with mGFR and non-association with demographic variables may represent candidate markers to improve estimation of GFR. [ABSTRACT FROM AUTHOR]

Background New equations to estimate glomerular filtration rate based on creatinine (eGFRcr), cystatin C (eGFRcys) or both (eGFRcr-cys) have been developed by the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) and the European Kidney Function Consortium (EKFC). There is a need to evaluate the performance of these equations in diverse European settings to inform implementation decisions, especially among people with key comorbid conditions. Methods We performed a cross-sectional study including 6174 adults referred for single-point plasma clearance of iohexol in Stockholm, Sweden, with 9579 concurrent measurements of creatinine and cystatin C. We assessed the performance of the CKD-EPI 2009/2012/2021, EKFC 2021/2023, revised Lund-Malmö (RLM) 2011 and Caucasian, Asian, Pediatric and Adult (CAPA) 2014 equations against measured GFR (mGFR). Results Mean age was 56 years, median mGFR was 62 mL/min/1.73 m2 and 40% were female. Comorbid conditions were common: cardiovascular disease (30%), liver disease (28%), diabetes (26%) and cancer (26%). All eGFRcr-cys equations had small bias and P30 (the percentage of estimated values within 30% of mGFR) close to 90%, and performed better than eGFRcr or eGFRcys equations. Among eGFRcr equations, CKD-EPI 2009 and CKD-EPI 2021 showed larger bias and lower P30 than EKFC 2021 and RLM. There were no meaningful differences in performance across eGFRcys equations. Findings were consistent across comorbid conditions, and eGFRcr-cys equations showed good performance in patients with liver disease, cancer and heart failure. Conclusions In conclusion, eGFRcr-cys equations performed best, with minimal variation among equations in this Swedish cohort. The lower performance of CKD-EPI eGFRcr equations compared with EKFC and RLM may reflect differences in population characteristics and mGFR methods. Implementing eGFRcr equations will require a trade-off between accuracy and uniformity across regions. [ABSTRACT FROM AUTHOR]

The commonly accepted glomerular filtration rate (GFR) threshold used to define chronic kidney disease is based on associations between estimated GFR (eGFR) and the frequency of adverse outcomes. However, the appropriateness of the threshold in older adults is uncertain, partly because the studies measuring these associations included relatively few outcomes and estimated GFR on the basis of creatinine level (eGFR cr), which may be less accurate in older adults. This study evaluated associations between eGFR cr versus eGFR based on creatinine and cystatin C levels and 8 outcomes in older adults. Visual Abstract. Association of Low Glomerular Filtration Rate With Adverse Outcomes at Older Age in a Large Population With Routinely Measured Cystatin C: The commonly accepted glomerular filtration rate (GFR) threshold used to define chronic kidney disease is based on associations between estimated GFR (eGFR) and the frequency of adverse outcomes. However, the appropriateness of the threshold in older adults is uncertain, partly because the studies measuring these associations included relatively few outcomes and estimated GFR on the basis of creatinine level (eGFR cr), which may be less accurate in older adults. This study evaluated associations between eGFR cr versus eGFR based on creatinine and cystatin C levels and 8 outcomes in older adults. Background: The commonly accepted threshold of glomerular filtration rate (GFR) to define chronic kidney disease (CKD) is less than 60 mL/min/1.73 m 2. This threshold is based partly on associations between estimated GFR (eGFR) and the frequency of adverse outcomes. The association is weaker in older adults, which has created disagreement about the appropriateness of the threshold for these persons. In addition, the studies measuring these associations included relatively few outcomes and estimated GFR on the basis of creatinine level (eGFR cr), which may be less accurate in older adults. Objective: To evaluate associations in older adults between eGFR cr versus eGFR based on creatinine and cystatin C levels (eGFR cr-cys) and 8 outcomes. Design: Population-based cohort study. Setting: Stockholm, Sweden, 2010 to 2019. Participants: 82 154 participants aged 65 years or older with outpatient creatinine and cystatin C testing. Measurements: Hazard ratios for all-cause mortality, cardiovascular mortality, and kidney failure with replacement therapy (KFRT); incidence rate ratios for recurrent hospitalizations, infection, myocardial infarction or stroke, heart failure, and acute kidney injury. Results: The associations between eGFR cr-cys and outcomes were monotonic, but most associations for eGFR cr were U-shaped. In addition, eGFR cr-cys was more strongly associated with outcomes than eGFR cr. For example, the adjusted hazard ratios for 60 versus 80 mL/min/1.73 m 2 for all-cause mortality were 1.2 (95% CI, 1.1 to 1.3) for eGFR cr-cys and 1.0 (CI, 0.9 to 1.0) for eGFR cr , and for KFRT they were 2.6 (CI, 1.2 to 5.8) and 1.4 (CI, 0.7 to 2.8), respectively. Similar findings were observed in subgroups, including those with a urinary albumin–creatinine ratio below 30 mg/g. Limitation: No GFR measurements. Conclusion: Compared with low eGFR cr in older patients, low eGFR cr-cys was more strongly associated with adverse outcomes and the associations were more uniform. Primary Funding Source: Swedish Research Council, National Institutes of Health, and Dutch Kidney Foundation. [ABSTRACT FROM AUTHOR]

Background While American nephrology societies recommend using the 2021 Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) estimated glomerular filtration rate (eGFR) equation without a Black race coefficient, it is unknown how this would impact disease distribution, prognosis and kidney failure risk prediction in predominantly White non-US populations. Methods We studied 1.6 million Stockholm adults with serum/plasma creatinine measurements between 2007 and 2019. We calculated changes in eGFR and reclassification across KDIGO GFR categories when changing from the 2009 to 2021 CKD-EPI equation; estimated associations between eGFR and the clinical outcomes kidney failure with replacement therapy (KFRT), (cardiovascular) mortality and major adverse cardiovascular events using Cox regression; and investigated prognostic accuracy (discrimination and calibration) of both equations within the Kidney Failure Risk Equation. Results Compared with the 2009 equation, the 2021 equation yielded a higher eGFR by a median [interquartile range (IQR)] of 3.9 (2.9–4.8) mL/min/1.73 m2, which was larger at older age and for men. Consequently, 9.9% of the total population and 36.2% of the population with CKD G3a–G5 was reclassified to a higher eGFR category. Reclassified individuals exhibited a lower risk of KFRT, but higher risks of all-cause/cardiovascular death and major adverse cardiovascular events, compared with non-reclassified participants of similar eGFR. eGFR by both equations strongly predicted study outcomes, with equal discrimination and calibration for the Kidney Failure Risk Equation. Conclusions Implementing the 2021 CKD-EPI equation in predominantly White European populations would raise eGFR by a modest amount (larger at older age and in men) and shift a major proportion of CKD patients to a higher eGFR category. eGFR by both equations strongly predicted outcomes. [ABSTRACT FROM AUTHOR]

Background Greater adherence to plant-based diets is associated with a lower risk of incident chronic kidney disease (CKD). Metabolomics can help identify blood biomarkers of plant-based diets and enhance understanding of underlying mechanisms. Objectives Using untargeted metabolomics, we aimed to identify metabolites associated with 4 plant-based diet indices (PDIs) (overall PDI, provegetarian diet, healthful PDI, and unhealthful PDI) and incident CKD in 2 subgroups within the Atherosclerosis Risk in Communities study. Methods We calculated 4 PDIs based on participants' responses on an FFQ. We used multivariable linear regression to examine the association between 4 PDIs and 374 individual metabolites, adjusting for confounders. We used Cox proportional hazards regression to evaluate associations between PDI-related metabolites and incident CKD. Estimates were meta-analyzed across 2 subgroups (n 1 = 1762; n 2 = 1960). We calculated C-statistics to assess whether metabolites improved the prediction of those in the highest quintile compared to the lower 4 quintiles of PDIs, and whether PDI- and CKD-related metabolites predicted incident CKD beyond the CKD prediction model. Results We identified 82 significant PDI–metabolite associations (overall PDI = 27; provegetarian = 17; healthful PDI = 20; unhealthful PDI = 18); 11 metabolites overlapped across the overall PDI, provegetarian diet, and healthful PDI. The addition of metabolites improved prediction of those in the highest quintile as opposed to the lower 4 quintiles of PDIs compared with participant characteristics alone (range of differences in C-statistics = 0.026–0.104; P value ≤ 0.001 for all tests). Six PDI-related metabolites (glycerate, 1,5-anhydroglucitol, γ-glutamylalanine, γ-glutamylglutamate, γ-glutamylleucine, γ-glutamylvaline), involved in glycolysis, gluconeogenesis, pyruvate metabolism, and γ-glutamyl peptide metabolism, were significantly associated with incident CKD and improved prediction of incident CKD beyond the CKD prediction model (difference in C-statistics for 6 metabolites = 0.005; P value = 0.006). Conclusions In a community-based study of US adults, we identified metabolites that were related to plant-based diets and predicted incident CKD. These metabolites highlight pathways through which plant-based diets are associated with incident CKD. [ABSTRACT FROM AUTHOR]

Importance: At a given estimated glomerular filtration rate (eGFR), individuals who are Black have higher rates of mortality and kidney failure with replacement therapy (KFRT) compared with those who are non-Black. Whether the recently adopted eGFR equations without race preserve racial differences in risk of mortality and KFRT at a given eGFR is unknown.Objective: To assess whether eGFR equations with and without race and cystatin C document racial differences in risk of KFRT and mortality in populations including Black and non-Black participants.Design, Setting, and Participants: Retrospective individual-level data analysis of 62 011 participants from 5 general population and 3 chronic kidney disease (CKD) US-based cohorts with serum creatinine, cystatin C, and follow-up for KFRT and mortality from 1988 to 2018.Exposures: Chronic Kidney Disease Epidemiology Collaboration equation with serum creatinine (eGFRcr with and without race), cystatin C (eGFRcys without race), or both markers (eGFRcr-cys without race).Main Outcomes and Measures: The prevalence of decreased eGFR at baseline and hazard ratios of KFRT and mortality in Black vs non-Black participants were calculated, adjusted for age and sex. Analyses were performed within each cohort and with random-effect meta-analyses of the models.Results: Among 62 011 participants (20 773 Black and 41 238 non-Black; mean age, 63 years; 53% women), the prevalence ratio (95% CI; percent prevalences) of eGFR less than 60 mL/min/1.73 m2 comparing Black with non-Black participants was 0.98 (95% CI, 0.93-1.03; 11% vs 12%) for eGFRcr with race, 0.95 (95% CI, 0.91-0.98; 17% vs 18%) for eGFRcys, and 1.2 (95% CI, 1.2-1.3; 13% vs 11%) for eGFRcr-cys but was 1.8 (95% CI, 1.7-1.8; 15% vs 9%) for eGFRcr without race. During a mean follow-up of 13 years, 8% and 4% of Black and non-Black participants experienced KFRT and 34% and 39% died, respectively. Decreased eGFR was associated with significantly greater risk of both outcomes for all equations. At an eGFR of 60 mL/min/1.73 m2, the hazard ratios for KFRT comparing Black with non-Black participants were 2.8 (95% CI, 1.6-4.9) for eGFRcr with race, 3.0 (95% CI, 1.5-5.8) for eGFRcys, and 2.8 (95% CI, 1.4-5.4) for eGFRcr-cys vs 1.3 (95% CI, 0.8-2.1) for eGFRcr without race. The 5-year absolute risk differences for KFRT comparing Black with non-Black participants were 1.4% (95% CI, 0.2%-2.6%) for eGFRcr with race, 1.1% (95% CI, 0.2%-1.9%) for eGFRcys, and 1.3% (95% CI, 0%-2.6%) for eGFRcr-cys vs 0.37% (95% CI, -0.32% to 1.05%) for eGFRcr without race. Similar patterns were observed for mortality.Conclusions and Relevance: In this retrospective analysis of 8 US cohorts including Black and non-Black individuals, the eGFR equation without race that included creatinine and cystatin C, but not the eGFR equation without race that included creatinine without cystatin C, demonstrated racial differences in the risk of KFRT and mortality throughout the range of eGFR. The eGFRcr-cys equation may be preferable to the eGFRcr equation without race for assessing racial differences in the risk of KFRT and mortality associated with low eGFR. [ABSTRACT FROM AUTHOR]

The article reviews the uses of glomerular filtration rate (GFR) and albuminuria level in testing for acute and chronic kidney disease (CKD). Topics discussed are clinical approach to detection, evaluation and management of acute kidney disease (AKD) and CKD, advances in clinical evaluation of GFR and albuminuria, risk factors for cardiovascular disease (CVD), eligibility criteria and end points for clinical trials of kidney disease progressions and risk prediction instruments for CKD outcomes.

Objective: Clinical guidelines for people with diabetes recommend chronic kidney disease (CKD) testing at least annually using estimated glomerular filtration rate (eGFR) and urinary albumin-to-creatinine ratio (uACR). We aimed to understand CKD testing among people with type 2 diabetes in the U.S.Research Design and Methods: Electronic health record data were analyzed from 513,165 adults with type 2 diabetes receiving primary care from 24 health care organizations and 1,164 clinical practice sites. We assessed the percentage of patients with both one or more eGFRs and one or more uACRs and each test individually in the 1, 2, and 3 years ending September 2019 by health care organization and clinical practice site. Elevated albuminuria was defined as uACR ≥30 mg/g.Results: The 1-year median testing rate across organizations was 51.6% for both uACR and eGFR, 89.5% for eGFR, and 52.9% for uACR. uACR testing varied (10th-90th percentile) from 44.7 to 63.3% across organizations and from 13.3 to 75.4% across sites. Over 3 years, the median testing rate for uACR across organizations was 73.7%. Overall, the prevalence of detected elevated albuminuria was 15%. The average prevalence of detected elevated albuminuria increased linearly with uACR testing rates at sites, with estimated prevalence of 6%, 15%, and 30% at uACR testing rates of 20%, 50%, and 100%, respectively.Conclusions: While eGFR testing rates are uniformly high among people with type 2 diabetes, testing rates for uACR are suboptimal and highly variable across and within the organizations examined. Guideline-recommended uACR testing should increase detection of CKD. [ABSTRACT FROM AUTHOR]

KDIGO Kidney Function and Disease Glossary: suggested terms to describe kidney function and kidney disease, and criteria and measures defining them. A coherent, shared nomenclature could improve communication at all levels, to not only foster better appreciation of the burden of disease but also aid understanding of how patients feel about their disease, allow more effective communication between kidney disease specialists and other clinicians, advance more straightforward comparison and integration of datasets, enable better recognition of gaps in knowledge for future research, and facilitate more comprehensive public health policies for acute and chronic kidney disease. [Extracted from the article]

Background A simple equation for glomerular filtration rate (GFR) measurement based on only plasma samples during the slow compartment after injection of iohexol was previously developed among children with chronic kidney disease and adult men with or at risk of HIV infection [Chronic Kidney Disease in Children (CKiD)-Multicenter AIDS Cohort Study (MACS) equation], but has not been externally validated. We aimed to evaluate the performance of the CKiD-MACS equation among elderly participants in the Multi-Ethnic Study of Atherosclerosis (MESA) cohort who underwent directly measured iohexol GFR. Methods Using data from 287 participants of the MESA-Kidney study who underwent a five-sample measured iohexol GFR (two and three samples in the fast and slow compartments, respectively), we assessed the performance of the CKiD-MACS equation using only plasma samples in the slow compartment by sex, race and age. Agreement was assessed by bias, correlation, proportion within 5 and 10%, and the root mean square error (RMSE). Results The average age and GFR of the participants were 71 years and 70.8 mL/min/1.73 m2, respectively, and 46% were black. The equation yielded excellent agreement within stratified groups with high correlation (>0.96), low bias (≤1.2 mL/min/1.73 m2) and low RMSE (<4.2 mL/min/1.73 m2). Conclusions The CKiD-MACS equation demonstrated valid GFR measurement using only samples in the slow compartment in this racially diverse, elderly population. While the equation yielded practically the same results as the original Brochner-Mortensen equation, the CKiD-MACS equation conforms to theoretical principles embedded in the two-compartment model of direct GFR measurement. [ABSTRACT FROM AUTHOR]

Evaluation of glomerular filtration rate (GFR) is central to the assessment of kidney function in medical practice, research and public health. Measured GFR (mGFR) remains the reference standard, but the past 20 years have seen major advances in estimated GFR (eGFR). Both eGFR and mGFR are associated with error compared with true GFR. eGFR is now recommended by clinical practice guidelines, regulatory agencies and public health agencies for the initial evaluation of GFR, with measured GFR (mGFR) typically considered an important confirmatory test, depending on how accurate the assessment of GFR needs to be for application to the clinical, research or public health setting. Our approach is to use initial and confirmatory tests as needed to develop a final assessment of true GFR. We suggest that GFR evaluation might be improved by more complete implementation of current recommendations and by further research to improve the accuracy of mGFR and eGFR. [ABSTRACT FROM AUTHOR]

Introduction: Chronic kidney disease (CKD) is a major public health challenge given its high global prevalence and associated risks of cardiovascular disease and progression to end stage renal disease. Although it is known that numerous metabolic changes occur in CKD patients, identifying novel metabolite associations with kidney function may enhance our understanding of the physiologic pathways relating to CKD. Objectives: The objective of this study was to elucidate novel metabolite associations with kidney function among participants of two community-based cohorts with carefully ascertained metabolomics, kidney function, and covariate data. Methods: Untargeted ultrahigh-performance liquid chromatography–tandem mass spectrometry was used to detect and quantify blood metabolites. We used multivariate adjusted linear regression to examine associations between single metabolites and creatinine-based estimated glomerular filtration rate (eGFRcr) among 1243 Bogalusa Heart Study (BHS) participants (median eGFRcr: 94.4, 5th–95th percentile: 66.0–119.6 mL/min/1.73 m2). Replication, determined by statistical significance and consistent effect direction, was tested using gold standard measured glomerular filtration rate (mGFR) among 260 Multi-Ethnic Study of Atherosclerosis (MESA) participants (median mGFR: 72.0, 5th–95th percentile: 43.5–105.0 mL/min/1.73 m2). All analyses used Bonferroni-corrected alpha thresholds. Results: Fifty-one novel metabolite associations with kidney function were identified, including 12 from previously unrelated sub-pathways: N6-carboxymethyllysine, gulonate, quinolinate, gamma-CEHC-glucuronide, retinol, methylmalonate, 3-hydroxy-3-methylglutarate, 3-aminoisobutyrate, N-methylpipecolate, hydroquinone sulfate, and glycine conjugates of C10H12O2 and C10H14O2(1). Significant metabolites were generally inversely associated with kidney function and smaller in mass-to-charge ratio than non-significant metabolites. Conclusion: The 51 novel metabolites identified may serve as early, clinically relevant, kidney function biomarkers. [ABSTRACT FROM AUTHOR]

Aims: Metformin could have benefits on cardiovascular disease and kidney disease progression but is often withheld from individuals with diabetes and chronic kidney disease (CKD) because of a concern that it may increase the risk of lactic acidosis. Materials and methods: All‐cause mortality, cardiovascular death, cardiovascular events (death, hospitalization for heart failure, myocardial infarction, stroke or myocardial ischemia), end stage renal disease (ESRD) and the kidney disease composite (ESRD or death) were compared in metformin users and non‐users with diabetes and CKD enrolled in the Trial to Reduce Cardiovascular Events with Aranesp (darbepoeitin‐alfa) Therapy (TREAT) (NCT00093015). Outcomes were compared after propensity matching of users and non‐users and in multivariable proportional hazards models. Results: There were 591 individuals who used metformin at baseline and 3447 non‐users. Among propensity‐matched users, the crude incidence rate for mortality, cardiovascular mortality, cardiovascular events and the combined endpoint was lower in metformin users than in non‐users, but ESRD was marginally higher (4.0% vs 3.6%). Metformin use was independently associated with a reduced risk of all‐cause mortality (HR, 0.49; 95% CI, 0.36‐0.69), cardiovascular death (HR, 0.49; 95% CI, 0.32‐0.74), the cardiovascular composite (HR, 0.67, 95% CI, 0.51‐0.88) and the kidney disease composite (HR, 0.77; 95% CI, 0.61‐0.98). Associations with ESRD (HR, 1.01; 95% CI, 0.65‐1.55) were not significant. Results were qualitatively similar in adjusted analyses of the full population. Two cases of lactic acidosis were observed. Conclusions: Metformin may be safer for use in CKD than previously considered and may lower the risk of death and cardiovascular events in individuals with stage 3 CKD. [ABSTRACT FROM AUTHOR]

Background: Dietary acid load is a clinically important aspect of the diet that reflects the balance between acid-producing foods, for example, meat and cheese, and base-producing foods, for example, fruits and vegetables.Methods: We used metabolomics to identify blood biomarkers of dietary acid load in 2 independent studies of chronic kidney disease patients: the African American Study of Kidney Disease and Hypertension (AASK, n = 689) and the Modification of Diet in Renal Disease (MDRD, n = 356) study. Multivariable linear regression was used to assess the cross-sectional association between serum metabolites whose identity was known (outcome) and dietary acid load (exposure), estimated with net endogenous acid production (NEAP) based on 24-h urine urea nitrogen and potassium, and adjusted for age, sex, race, randomization group, measured glomerular filtration rate, log-transformed urine protein-to-creatinine ratio, history of cardiovascular disease, BMI, and smoking status.Results: Out of the 757 known, nondrug metabolites identified in AASK, 26 were significantly associated with NEAP at the Bonferroni threshold for significance (P < 6.6 × 10-5). Twenty-three of the 26 metabolites were also identified in the MDRD study, and 13 of the 23 (57%) were significantly associated with NEAP (P < 2.2 × 10-3), including 5 amino acids (S-methylmethionine, indolepropionylglycine, indolepropionate, N-methylproline, N-δ-acetylornithine), 2 cofactors and vitamins (threonate, oxalate), 1 lipid (chiro-inositol), and 5 xenobiotics (methyl glucopyranoside, stachydrine, catechol sulfate, hippurate, and tartronate). Higher levels of all 13 replicated metabolites were associated with lower NEAP in both AASK and the MDRD study.Conclusion: Metabolomic profiling of serum specimens from kidney disease patients in 2 study populations identified 13 replicated metabolites associated with dietary acid load. Additional studies are needed to validate these compounds in healthy populations. These 13 compounds may potentially be used as objective markers of dietary acid load in future nutrition research studies. [ABSTRACT FROM AUTHOR]

Background: Uromodulin is a kidney-derived glycoprotein and putative tubular function index. Lower serum uromodulin was recently associated with increased risk for kidney allograft failure in a preliminary, longitudinal single-center -European study involving 91 kidney transplant recipients (KTRs).Methods: The Folic Acid for Vascular Outcome Reduction in Transplantation (FAVORIT) trial is a completed, large, multiethnic controlled clinical trial cohort, which studied chronic, stable KTRs. We conducted a case cohort analysis using a randomly selected subset of patients (random subcohort, n = 433), and all individuals who developed kidney allograft failure (cases, n = 226) during follow-up. Serum uromodulin was determined in this total of n = 613 FAVORIT trial participants at randomization. Death-censored kidney allograft failure was the study outcome.Results: The 226 kidney allograft failures occurred during a median surveillance of 3.2 years. Unadjusted, weighted Cox proportional hazards modeling revealed that lower serum uromodulin, tertile 1 vs. tertile 3, was associated with a threefold greater risk for kidney allograft failure (hazards ratio [HR], 95% CI 3.20 [2.05-5.01]). This association was attenuated but persisted at twofold greater risk for allograft failure, after adjustment for age, sex, smoking, allograft type and vintage, prevalent diabetes mellitus and cardiovascular disease (CVD), total/high-density lipoprotein cholesterol ratio, systolic blood pressure, estimated glomerular filtration rate, and natural log urinary albumin/creatinine: HR 2.00, 95% CI (1.06-3.77).Conclusions: Lower serum uromodulin, a possible indicator of less well-preserved renal tubular function, remained associated with greater risk for kidney allograft failure, after adjustment for major, established clinical kidney allograft failure and CVD risk factors, in a large, multiethnic cohort of long-term, stable KTRs. [ABSTRACT FROM AUTHOR]

Background. The Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations are recommended for glomerular filtration rate (GFR) estimation in the general population. They have not been evaluated in community-based populations, including Blacks at higher levels of GFR, but are commonly applied in such populations. Methods. In an ancillary study of Multi-Ethnic Study of Atherosclerosis conducted at one site, we evaluated the performance of the CKD-EPI equations for creatinine (eGFRcr), cystatin C (eGFRcys) or the combination (eGFRcr-cys) compared with GFR measured as plasma clearance of iohexol. Results. Among 294 participants, the mean age was 71 (SD 9) years, 47% were Black, 48% were women and themean measured GFR (mGFR) was 72.6 (SD 18.8) mL/min/1.73 m2. The CKDEPI equations overestimated mGFR with a larger median bias for eGFRcr and eGFRcr-cys than eGFRcys [-8.3 (95% confidence interval -9.7, -6.5), -7.8 (-9.2, -6.2) and -3.7 (-5.0, -1.8) mL/min/1.73 m2, respectively], with smaller bias for those with lower compared with higher eGFR and by race compared with sex. Conclusion. The small differential bias of the CKD-EPI equation between races suggests that they can be used in Blacks as well as Whites in older community-based adults. The large differential bias in women versus men in all equations is in contrast to other studies and is unexplained. Further studies are required in multiracial and multiethnic community-based cohorts, taking into account differences in GFR measurement methods. [ABSTRACT FROM AUTHOR]

Background: The pathogenesis of chronic kidney disease associated anemia is multifactorial and includes decreased production of erythropoietin (EPO), iron deficiency, inflammation, and EPO resistance. To better understand the trajectory of these parameters, we described temporal trends in hemoglobin (Hb), ferritin, transferrin saturation, C-reactive protein (CRP), and darbepoetin dosing in the Trial to Reduce cardiovascular Events with Aranesp Therapy (TREAT).Methods: We performed a post hoc analysis of 4,038 participants in TREAT. Mixed effects linear regression models were used to determine the trajectory of parameters of interest prior to end-stage renal disease (ESRD). Likelihood ratio tests were used to determine the overall differences in biomarker values and differences in trajectories between those who did and did not develop ESRD.Results: Hb declined precipitously in the year prior to the development of ESRD (irrespective of treatment assignment), and was on average 1.15 g/dL (95% CI -1.26 to -1.04) lower in those who developed ESRD versus those who did not, at the time of ESRD/end of follow-up. Simultaneously, the mean darbepoetin dose and CRP concentration increased, while serum ferritin and transferrin saturations were >140 μg/L and 20%, respectively.Conclusions: Our analyses provide descriptive insights regarding the temporal changes of Hb, darbepoetin dose, and related parameters as ESRD approaches in participants of TREAT. Hb declined as much as 1-2 years prior to the development of ESRD, without biochemical evidence of iron deficiency. The most precipitous decline occurred in the months immediately prior to ESRD, despite administration of escalating doses of darbepoetin and in parallel with an increase in CRP. [ABSTRACT FROM AUTHOR]

Background Glomerular filtration rate (GFR) estimating equations using the combination of creatinine and cystatin C (eGFRcr-cys) are more accurate than equations using either alone (eGFRcr or eGFRcys). New guidelines suggest measuring cystatin C as a confirmatory test when eGFRcr may be inaccurate, but do not specify demographic or clinical conditions in which eGFRcys or eGFRcr-cys are more accurate than eGFRcr nor which estimate to use in such circumstances. Methods We compared the performance of the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations in 1119 subjects in the CKD-EPI cystatin C external validation dataset. Subgroups were defined by eGFRcr, age, sex, diabetes status and body mass index (BMI). The reference test was GFR measured using urinary or plasma clearance of exogenous filtration markers. Cystatin C and creatinine assays were traceable to primary reference materials. Accuracy was defined as the absolute difference in eGFR compared with mGFR. Results The mean mGFR was 70 ± 41 (SD) mL/min/1.73 m2. eGFRcys was more accurate than eGFRcr at lower BMI and less accurate at higher BMI, especially at higher levels of eGFRcr. There were small differences in accuracy in people according to the diabetes status. eGFRcr-cys was as accurate or more accurate than eGFRcr or eGFRcys in these and all other subgroups. Conclusions eGFRcr-cys, but not eGFRcys, is more accurate than eGFRcr in most subgroups we studied, suggesting preferential use of eGFRcr-cys when serum cystatin C is measured as a confirmatory test to obtain more accurate eGFR. Further studies are necessary to evaluate diagnostic strategies for using eGFRcys and eGFRcr-cys. [ABSTRACT FROM PUBLISHER]

The article focuses on the description and implication of chronic kidney disease. It says that chronic kidney disease is a common term for heterogeneous disorders which affects the function and structure of the kidney. It states that the disease can be observed with routine laboratory test, and some of its treatment can reduce disease progression, and decrease complications of reduced glomerular filtration rate (GFR), and improve quality of life and survival.

The definition and classification for chronic kidney disease was proposed by the National Kidney Foundation Kidney Disease Outcomes Quality Initiative (NKF-KDOQI) in 2002 and endorsed by the Kidney Disease: Improving Global Outcomes (KDIGO) in 2004. This framework promoted increased attention to chronic kidney disease in clinical practice, research and public health, but has also generated debate. It was the position of KDIGO and KDOQI that the definition and classification should reflect patient prognosis and that an analysis of outcomes would answer key questions underlying the debate. KDIGO initiated a collaborative meta-analysis and sponsored a Controversies Conference in October 2009 to examine the relationship of estimated glomerular filtration rate (GFR) and albuminuria to mortality and kidney outcomes. On the basis of analyses in 45 cohorts that included 1,555,332 participants from general, high-risk, and kidney disease populations, conference attendees agreed to retain the current definition for chronic kidney disease of a GFR <60 ml/min per 1.73 m2 or a urinary albumin-to-creatinine ratio >30 mg/g, and to modify the classification by adding albuminuria stage, subdivision of stage 3, and emphasizing clinical diagnosis. Prognosis could then be assigned based on the clinical diagnosis, stage, and other key factors relevant to specific outcomes. KDIGO has now convened a workgroup to develop a global clinical practice guideline for the definition, classification, and prognosis of chronic kidney disease. [ABSTRACT FROM AUTHOR]

The article discusses a study that aimed to develop and validate predictive models for progression of chronic kidney disease (CKD). Estimated glomerular filtration rate (GFR) and albuminuria are described as classifications of the severity of kidney disease. Development and validation cohort studies were conducted which included more than 3,000 Canadian patients with CKD of stages 3 to 5. The models were developed using Cox proportional hazards regression methods. The results show that a model utilizing routinely obtained laboratory tests can accurately predict progression to kidney failure in stages 3-5 CKD patients.

Background. Kidney failure is associated with muscle wasting and physical impairment. Moderate- to high-intensity strength training improves physical performance, nutritional status and quality of life in people with chronic kidney disease and in dialysis patients. However, the effect of low-intensity strength training has not been well documented, thus representing the objective of this pilot study. [ABSTRACT FROM PUBLISHER]

This article presents the results of a study to determine the prevalence of chronic kidney disease (CKD) in the U.S. CKD is recognized as a common condition that increases the risks of heart disease and kidney failure. The number of people suffering from CKD who are on dialysis or had a transplant increased from 209,000 in 1991 to 472,000 in 2004. The authors wanted to see if there has been an increase in the earlier stages of CKD as defined on the basis of kidney damage and decreased kidney function. The study showed that the rate of the early stage CKD is higher in 10999-2004 than it was in 1988-1994.

The article examines whether cardiovascular disease (CVD) is a risk factor for progression or development of kidney disease. It discusses the use of multivariate logistic regression analysis to determine the association between CVD and outcomes. The article shows that CVD is independently associated with kidney function decline and with the development of kidney disease.

The author reflects on the threat of chronic kidney disease (CKD) on global public health. He cited the medical statistics in the U.S. from the U.S. National Health and Nutrition Examination Survey, which estimate the prevalence of CKD as 9.6% in non-institutionalized adults, or about 19 million people, as evidence of the poised threat of CKD on public health. Advances in treatment of CKD made him realize that it is time to establish policies in order to translate these to public health.

Background: Glomerular filtration rate (GFR) estimates facilitate detection of chronic kidney disease but require calibration of the serum creatinine assay to the laboratory that developed the equation. The 4-variable equation from the Modification of Diet in Renal Disease (MDRD) Study has been reexpressed for use with a standardized assay. Objective: To describe the performance of the revised 4-variable MDRD Study equation and compare it with the performance of the 6-variable MDRD Study and Cockcroft-Gault equations. Design: Comparison of estimated and measured GFR. Setting: 15 clinical centers participating in a randomized, controlled trial. Patients: 1628 patients with chronic kidney disease participating in the MDRD Study. Measurements: Serum creatinine levels were calibrated to an assay traceable to isotope-dilution mass spectrometry. Glomerular filtration rate was measured as urinary clearance of 125I-iothalamate. Results: Mean measured GFR was 39.8 mL/min per 1.73 m² (SD, 21.2). Accuracy and precision of the revised 4-variable equation were similar to those of the original 6-variable equation and better than in the Cockcroft-Gault equation, even when the latter was corrected for bias, with 90%, 91%, 60%, and 83% of estimates within 30% of measured GFR, respectively. Differences between measured and estimated GFR were greater for all equations when the estimated GFR was 60 mL/min per 1.73 m² or greater. Limitations: The MDRD Study included few patients with a GFR greater than 90 mL/min per 1.73 m2. Equations were not compared in a separate study sample. Conclusions: The 4-variable MDRD Study equation provides reasonably accurate GFR estimates in patients with chronic kidney disease and a measured GFR of less than 90 mL/min per 1.73 m². By using the reexpressed MDRD Study equation with the standardized serum creatinine assay, clinical laboratories can report more accurate GFR estimates. [ABSTRACT FROM AUTHOR]

Background: The influence of type of dialysis on survival of patients with end-stage renal disease (ESRO) is controversial. Objective: To compare risk for death among patients with ESRO who receive peritoneal dialysis or hemodialysis. Design: Prospective cohort study. Setting: 81 dialysis clinics in 19 U.S. states. Patients: 1041 patients starting dialysis (274 patients receiving peritoneal dialysis and 767 patients receiving hemodialysis) at baseline. Measurements: Patients were followed for up to 7 years and censored at transplantation or loss to follow-up. Cox proportional hazards regression stratified by clinic was used to compare the risk for death with peritoneal dialysis versus hemodialysis. Results: Twenty-five percent of patients undergoing peritoneal dialysis and 5% of hemodialysis patients switched type of dialysis. After adjustment the risk for death did not differ between patients undergoing peritoneal dialysis and those undergoing hemodialysis during the first year (relative hazard, 1.39 [95% CI, 0.64 to 3.06]), but the risk became significantly higher among those undergoing peritoneal dialysis in the second year (relative hazard, 2.34 [CI, 1.19 to 4.59]). After stratification, the survival rate was no different for patients who had the highest propensity of being initially treated with peritoneal dialysis. Results were consistent with adjustment based on a propensity score model and in sensitivity analyses that used as-treated models and models in which switches in type of dialysis were treated as treatment failures. Results were similar but stronger in analyses that were restricted to patients who were treated only in clinics offering both types of dialysis. Limitations: Patients were not randomly assigned to their initial type of dialysis. Also, more patients undergoing peritoneal dialysis than hemodialysis switched type of dialysis over time, and the reason for switching was often a consequence of the technique. Conclusions: The risk for death in patients with ESRO under- going dialysis depends on dialysis type. Further studies are needed to evaluate a possible survival benefit of a timely change from peritoneal dialysis to hemodialysis. [ABSTRACT FROM AUTHOR]

Definition and classification of chronic kidney disease: A position statement from Kidney Disease: Improving Global Outcomes (KDIGO). Chronic kidney disease (CKD) is a worldwide public health problem, with adverse outcomes of kidney failure, cardiovascular disease (CVD), and premature death. A simple definition and classification of kidney disease is necessary for international development and implementation of clinical practice guidelines. Kidney Disease: Improving Global Outcomes (KDIGO) conducted a survey and sponsored a controversies conference to (1) provide a clear understanding to both the nephrology and nonnephrology communities of the evidence base for the definition and classification recommended by Kidney Disease Quality Outcome Initiative (K/DOQI), (2) develop global consensus for the adoption of a simple definition and classification system, and (3) identify a collaborative research agenda and plan that would improve the evidence base and facilitate implementation of the definition and classification of CKD.The K/DOQI definition and classification were accepted, with clarifications. CKD is defined as kidney damage or glomerular filtration rate (GFR)<60 mL/min/1.73 m2 for 3 months or more, irrespective of cause. Kidney damage in many kidney diseases can be ascertained by the presence of albuminuria, defined as albumin-to-creatinine ratio>30 mg/g in two of three spot urine specimens. GFR can be estimated from calibrated serum creatinine and estimating equations, such as the Modification of Diet in Renal Disease (MDRD) Study equation or the Cockcroft-Gault formula. Kidney disease severity is classified into five stages according to the level of GFR. Kidney disease treatment by dialysis and transplantation should be noted. Simple, uniform classifications of CKD by cause and by risks for kidney disease progression and CVD should be developed. [ABSTRACT FROM AUTHOR]

The National Kidney Foundation developed and oversees the Kidney Disease Outcomes Quality Initiative, a process that develops clinical practice guidelines in nephrology. Recent guidelines address the evaluation, classification, and stratification of chronic kidney disease (CKD). These guidelines provide, for the first time, a standard definition of CKD, classification of its stages, and suggestions for appropriate laboratory measurements for the assessment of kidney function. Also discussed are the association of level of kidney function with systemic complications that develop during CKD, and the risk of loss of kidney function and development of cardiovascular disease in CKD. [ABSTRACT FROM AUTHOR]

Summarizes guidelines for using tests to evaluate patients with suspected or known chronic kidney disease, published by the National Kidney Foundation in February 2002. Estimation of glomerular filtration rate; Assessment of proteinuria; Other markers for chronic kidney disease.

Individuals with chronic kidney disease (CKD) are at increased risk for the development and progression of cardiovascular disease (CVD). The increased risk is due to a higher prevalence of both traditional risk factors as well as nontraditional risk factors. In this review we focus on individuals at all stages of CKD and discuss modifiable traditional risk factors, namely hypertension, dyslipidemia, diabetes mellitus and poor glycemic control, smoking, and physical inactivity. The prevalence of each risk factor and its relationship with CVD is described. Treatment recommendations are provided using evidence available from populations with CKD or evidence extrapolated from the general population when there are insufficient data on individuals with CKD. [ABSTRACT FROM AUTHOR]

The purpose of this paper is to describe the ICED, summarize outcomes of prior studies in which it was used, and describe the adaptations that have lead to the present instrument. We will then demonstrate its use in quantifying the burden of comorbid conditions in a sample of hemodialysis and peritoneal dialysis patients from our center, and show the relationship between ICED levels and outcomes in peritoneal dialysis patients. [ABSTRACT FROM AUTHOR]

Objective: To describe the clinical course of severe lupus nephritis and to identify the risk factors for progression to renal failure among patients treated with prednisone and short-term courses of low-dose oral cyclophosphamide.Design: Ancillary analyses of data from the Lupus Nephritis Collaborative Study (LNCS).Setting: University hospital medical centers (14).Patients: The 86 patients who participated in the LNCS (mean follow-up, 136 weeks [2.6 years]) and a subgroup of 63 patients with follow-up of more than 48 weeks (mean follow-up, 160 weeks [3.1 years]).Measurements: Initial clinical and pathologic features, response to therapy within 48 weeks, and subsequent clinical events, including development of renal failure.Main Results: Renal failure developed in 18 patients (21%). An observed elevation in serum creatinine concentration was the only initial feature predictive of subsequent renal failure. Mean (+/- SD) initial serum creatinine levels were higher in patients who subsequently developed renal failure (244 +/- 134 mumol/L [2.76 +/- 1.52 mg/dL] compared with 163 +/- 103 mumol/L [1.85 +/- 1.17 mg/dL]; P = 0.007). The risk for renal failure was higher among patients with initial serum creatinine levels greater than 106 mumol/L (1.2 mg/dL) (29% compared with 6.5%; P = 0.014). Response to therapy (defined as resolution of initial serum creatinine elevations within 48 weeks) refined the prognosis based on initial serum creatinine determinations. The risk for subsequent renal failure was higher among patients who failed to respond to therapy within 48 weeks (30% compared with 0%; P = 0.015). By comparison, 9% of patients with normal initial serum creatinine levels progressed to renal failure after 48 weeks.Conclusions: Initial serum creatinine levels and responses to initial therapy with prednisone and short-term cyclophosphamide, as used in the LNCS, can guide further therapy. Patients with normal initial serum creatinine levels or resolution of initial serum creatinine elevations within 48 weeks have a low risk for renal failure and may not require long-term treatment with cyclophosphamide. [ABSTRACT FROM AUTHOR]

Jorge and colleagues examined data from 1995 to 2014 to assess outcomes of patients with lupus nephritis who initiated dialysis and were placed on the waitlist for a kidney transplant. The editorialists discuss the findings in light of slow progress in the treatment of lupus nephritis. Given higher patient and allograft survival with both preemptive and early kidney transplant, it is essential that transplant be considered as promptly as possible for patients with lupus nephritis. [ABSTRACT FROM AUTHOR]

The article presents the authors' opinions rejecting calls for U.S. medical guidelines to be amended to require age calibration for diagnosis and classification of chronic kidney disease (CKD). Topics addressed include assertions that treatments should be tailored for age differences but the disease should not be redefined, commentary on the broad consensus and acceptance of the current guidelines, and assertions that just because CKD is common in older people it is not necessarily normative.

The article presents reply of the author on their article on managing Chronic Kidney Disease (CKD) in older people is presented.

The article discusses a study on whether associations of estimated glomerular filtration rate (eGFR) and albuminuria with outcomes of mortality, cardiovascular mortality, and end stage renal disease differ by sex. It discusses that low eGFR and albuminuria are the main causes of mortality. It is concluded that there is no evidence of a sex difference in the associations of eGFR and albumin-creatinine ratio with risk of end stage renal disease.

The article describes the risk factors associated with chronic kidney disease in the elderly patients. Chronic kidney disease is associated with a high risk of kidney failure, cardiovascular disease, and death. The severity of chronic kidney disease can be classified according to the level of the glomerular filtration rate (GFR). It has been evidenced that chronic kidney disease is an independent risk factor for cardiovascular disease. In a recent study, the researchers examined the association of measures of kidney function with mortality and cardiovascular disease during the last 10 years. It was concluded that the increased risk of cardiovascular disease among elderly patients with chronic kidney disease may occur at higher levels of GFR than previously suspected.

Background: Evaluation of candidates to serve as living kidney donors relies on screening for individual risk factors for end-stage renal disease (ESRD). To support an empirical approach to donor selection, we developed a tool that simultaneously incorporates multiple health characteristics to estimate a person's probable long-term risk of ESRD if that person does not donate a kidney.Methods: We used risk associations from a meta-analysis of seven general population cohorts, calibrated to the population-level incidence of ESRD and mortality in the United States, to project the estimated long-term incidence of ESRD among persons who do not donate a kidney, according to 10 demographic and health characteristics. We then compared 15-year projections with the observed risk among 52,998 living kidney donors in the United States.Results: A total of 4,933,314 participants from seven cohorts were followed for a median of 4 to 16 years. For a 40-year-old person with health characteristics that were similar to those of age-matched kidney donors, the 15-year projections of the risk of ESRD in the absence of donation varied according to race and sex; the risk was 0.24% among black men, 0.15% among black women, 0.06% among white men, and 0.04% among white women. Risk projections were higher in the presence of a lower estimated glomerular filtration rate, higher albuminuria, hypertension, current or former smoking, diabetes, and obesity. In the model-based lifetime projections, the risk of ESRD was highest among persons in the youngest age group, particularly among young blacks. The 15-year observed risks after donation among kidney donors in the United States were 3.5 to 5.3 times as high as the projected risks in the absence of donation.Conclusions: Multiple demographic and health characteristics may be used together to estimate the projected long-term risk of ESRD among living kidney-donor candidates and to inform acceptance criteria for kidney donors. (Funded by the National Institute of Diabetes and Digestive and Kidney Diseases and others.). [ABSTRACT FROM AUTHOR]

A response by Saulo Klahr, Andrew S. Levey and Gerald J. Beck to a letter to the editor about their article related to the effects of dietary protein restriction and blood-pressure control on the progression of chronic renal insufficiency in the March 31, 1994 issue is presented.

Living kidney donation benefits recipients and society but carries short-term and long-term risks for the donor. This Review summarizes the studies that underlie our current understanding of these risks in the first decade after donation, with a view to improving the informed consent process. Two studies report a higher risk of end-stage renal disease (ESRD) among donors than among healthy nondonors; however, the absolute 15-year incidence of ESRD is <1%. All-cause mortality and the risk of cardiovascular events are similar among donors and healthy nondonors, although one study provides evidence for a 5% increase in all-cause mortality after 25 years that is attributable to donation. Some evidence suggests that the 20-year incidence of gout is slightly higher among donors than among healthy nondonors. The risks of gestational hypertension or pre-eclampsia seem to be 6% higher in pregnancies among donors than in pregnancies among healthy nondonors. The incidences of acute kidney injury, kidney stones that require surgical intervention, gastrointestinal bleeding and fractures seem no higher among donors than among healthy nondonors, although some of these conclusions are based on a small number of events. Future studies must clarify the lifetime incidence of long-term outcomes, particularly in relation to a donor's age, race, and history of comorbidities. [ABSTRACT FROM AUTHOR]

Current guidelines recommend under 2 g/day sodium intake in chronic kidney disease, but there are a few studies relating sodium intake to long-term outcomes. Here we evaluated the association of mean baseline 24-h urinary sodium excretion with kidney failure and a composite outcome of kidney failure or all-cause mortality using Cox regression in 840 participants enrolled in the Modification of Diet in Renal Disease Study. Mean 24-h urinary sodium excretion was 3.46 g/day. Kidney failure developed in 617 participants, and the composite outcome was reached in 723. In the primary analyses, there was no association between 24-h urine sodium and kidney failure (HR 0.99 (95% CI 0.91-1.08)) nor on the composite outcome (HR 1.01 (95% CI 0.93-1.09)), each per 1 g/day higher urine sodium. In exploratory analyses, there was a significant interaction of baseline proteinuria and sodium excretion with kidney failure. Using a two-slope model, when urine sodium was under 3 g/day, higher urine sodium was associated with increased risk of kidney failure in those with baseline proteinuria under 1 g/day and with lower risk of kidney failure in those with baseline proteinuria of ⩾1 g/day. There was no association between urine sodium and kidney failure when urine sodium was⩾3 g/day. Results were consistent using first baseline and time-dependent urinary sodium excretion. Thus, we noted no association of urine sodium with kidney failure. Results of the exploratory analyses need to be verified in additional studies and the mechanism explored. [ABSTRACT FROM AUTHOR]

The global nephrology community recognises the need for a cohesive plan to address the problem of chronic kidney disease (CKD). In July, 2016, the International Society of Nephrology hosted a CKD summit of more than 85 people with diverse expertise and professional backgrounds from around the globe. The purpose was to identify and prioritise key activities for the next 5-10 years in the domains of clinical care, research, and advocacy and to create an action plan and performance framework based on ten themes: strengthen CKD surveillance; tackle major risk factors for CKD; reduce acute kidney injury-a special risk factor for CKD; enhance understanding of the genetic causes of CKD; establish better diagnostic methods in CKD; improve understanding of the natural course of CKD; assess and implement established treatment options in patients with CKD; improve management of symptoms and complications of CKD; develop novel therapeutic interventions to slow CKD progression and reduce CKD complications; and increase the quantity and quality of clinical trials in CKD. Each group produced a prioritised list of goals, activities, and a set of key deliverable objectives for each of the themes. The intended users of this action plan are clinicians, patients, scientists, industry partners, governments, and advocacy organisations. Implementation of this integrated comprehensive plan will benefit people who are at risk for or affected by CKD worldwide. [ABSTRACT FROM AUTHOR]

Some suggest race-specific cutpoints for kidney measures to define and stage chronic kidney disease (CKD), but evidence for race-specific clinical impact is limited. To address this issue, we compared hazard ratios of estimated glomerular filtration rates (eGFR) and albuminuria across races using meta-regression in 1.1 million adults (75% Asians, 21% Whites, and 4% Blacks) from 45 cohorts. Results came mainly from 25 general population cohorts comprising 0.9 million individuals. The associations of lower eGFR and higher albuminuria with mortality and end-stage renal disease (ESRD) were largely similar across races. For example, in Asians, Whites, and Blacks, the adjusted hazard ratios (95% confidence interval) for eGFR 45-59 versus 90-104 ml/min per 1.73 m2 were 1.3 (1.2-1.3), 1.1 (1.0-1.2), and 1.3 (1.1-1.7) for all-cause mortality, 1.6 (1.5-1.7), 1.4 (1.2-1.7), and 1.4 (0.7-2.9) for cardiovascular mortality, and 27.6 (11.1-68.7), 11.2 (6.0-20.9), and 4.1 (2.2-7.5) for ESRD, respectively. The corresponding hazard ratios for urine albumin-to-creatinine ratio 30-299 mg/g or dipstick 1+ versus an albumin-to-creatinine ratio under 10 or dipstick negative were 1.6 (1.4-1.8), 1.7 (1.5-1.9), and 1.8 (1.7-2.1) for all-cause mortality, 1.7 (1.4-2.0), 1.8 (1.5-2.1), and 2.8 (2.2-3.6) for cardiovascular mortality, and 7.4 (2.0-27.6), 4.0 (2.8-5.9), and 5.6 (3.4-9.2) for ESRD, respectively. Thus, the relative mortality or ESRD risks of lower eGFR and higher albuminuria were largely similar among three major races, supporting similar clinical approach to CKD definition and staging, across races. [ABSTRACT FROM AUTHOR]