Comparing the association of GFR estimated by the CKD-EPI and MDRD study equations and mortality: the third national health and nutrition examination survey (NHANES III)

BACKGROUND: The Chronic Kidney Disease Epidemiology Collaboration equation for estimation of glomerular filtration rate (eGFR(CKD-EPI)) improves GFR estimation compared with the Modification of Diet in Renal Disease Study equation (eGFR(MDRD)) but its association with mortality in a nationally representative population sample in the US has not been studied. METHODS: We examined the association between eGFR and mortality among 16,010 participants of the Third National Health and Nutrition Examination Survey (NHANES III). Primary predictors were eGFR(CKD-EPI) and eGFR(MDRD). Outcomes of interest were all-cause and cardiovascular disease (CVD) mortality. Improvement in risk categorization with eGFR(CKD-EPI) was evaluated using adjusted relative hazard (HR) and Net Reclassification Improvement (NRI). RESULTS: Overall, 26.9% of the population was reclassified to higher eGFR categories and 2.2% to lower eGFR categories by eGFR(CKD-EPI,) reducing the proportion of prevalent CKD classified as stage 3–5 from 45.6% to 28.8%(.) There were 3,620 deaths (1,540 from CVD) during 215,082 person-years of follow-up (median, 14.3 years). Among those with eGFR(MDRD) 30–59 ml/min/1.73 m(2), 19.4% were reclassified to eGFR(CKD-EPI) 60–89 ml/min/1.73 m(2) and these individuals had a lower risk of all-cause mortality (adjusted HR, 0.53; 95% CI, 0.34-0.84) and CVD mortality (adjusted HR, 0.51; 95% CI, 0.27-0.96) compared with those not reclassified. Among those with eGFR(MDRD) >60 ml/min/1.73 m(2), 0.5% were reclassified to lower eGFR(CKD-EPI) and these individuals had a higher risk of all-cause (adjusted HR, 1.31; 95% CI, 1.01-1.69) and CVD (adjusted HR, 1.42; 95% CI, 1.01-1.99) mortality compared with those not reclassified. Risk prediction improved with eGFR(CKD-EPI); NRI was 0.21 for all-cause mortality (p < 0.001) and 0.22 for CVD mortality (p < 0.001). CONCLUSIONS: eGFR(CKD-EPI) categories improve mortality risk stratification of individuals in the US population. If eGFR(CKD-EPI) replaces eGFR(MDRD) in the US, it will likely improve risk stratification

Treating Early-Stage CKD With New Medication Therapies:Results of a CKD Patient Survey Informing the 2020 NKF-FDA Scientific Workshop on Clinical Trial Considerations for Developing Treatments for Early Stages of Common, Chronic Kidney Diseases

RATIONALE & OBJECTIVE: With a growing number of medications and therapies available to treat chronic kidney disease (CKD), risk-versus-benefit discussions are increasingly critical. Balancing risks and benefits requires assessing patients’ understanding of these, as well as incorporating patient preferences and tolerance for side effects into shared decision making. STUDY DESIGN: A 26-question online survey was sent to people in the National Kidney Foundation patient email list and posted on associated social media pages to assess the respondents’ willingness and comfort with taking preventative medications during earlier-stage CKD to inform a December 2020 scientific workshop co-sponsored by the National Kidney Foundation and the US Food and Drug Administration on clinical trial considerations in developing treatments for individuals with early stages of CKD. SETTING & POPULATION: Online survey of CKD patients, including broad demographic data and responses to risk-benefit scenarios, with surveys emailed to 20,249 people not identified as currently receiving kidney replacement therapy. ANALYTICAL APPROACH: Survey results are presented as descriptive data. RESULTS: Of 1,029 respondents, 45 self-identified as at risk for CKD, 566 had CKD, 267 had received kidney transplants, 51 were receiving dialysis, and 100 replied other or did not answer. Respondents reported being willing to assume some risk with the goal of preventing the progression of CKD, with a greater willingness to assume risk and treatment burdens the closer they came to late-stage disease. Clinician recommendations regarding kidney therapies and clinician willingness to work with patients to address any side effects were important in respondents’ willingness to initiate and persevere with a new medication. LIMITATIONS: Approximately 10% response rate with limited data on respondents. CONCLUSIONS: Risk-versus-benefit discussions appear key to patients and their care partners making well-informed decisions about taking a new medication that may or may not help the progression of their kidney disease. Future tools and strategies are needed to facilitate informed discussions of treatment in early-stage kidney disease

Effects of newer kidney protective agents on kidney endpoints provide implications for future clinical trials

Doubling of serum creatinine (equivalent to a 57% decline in the estimated glomerular filtration rate (eGFR)) is an accepted component of a composite kidney endpoint in clinical trials. Smaller declines in eGFR (40%, 50%) have been applied in several recently conducted clinical trials. Here, we assessed the effects of newer kidney protective agents on endpoints including smaller proportional declines in eGFR to compare relative event rates and the magnitude of observed treatment effects. We performed a post hoc analysis of 4401 patients in the CREDENCE, 4304 in the DAPA-CKD, 5734 in the FIDELIO-DKD, and 3668 in the SONAR trials, which assessed the effects of canagliflozin, dapagliflozin, finerenone and atrasentan in patients with chronic kidney disease. Effects of active therapies versus placebo on alternative composite kidney endpoints incorporating different eGFR decline thresholds (40%, 50%, or 57% eGFR reductions from baseline) with kidney failure or death due to kidney failure were compared. Cox-proportional hazards regression models were used to assess and compare treatment effects. During follow-up, event rates were higher for endpoints incorporating smaller versus larger eGFR decline thresholds. Compared to the treatment effects on kidney failure or death due to kidney failure, the magnitude of relative treatment effects was generally similar when considering composite endpoints incorporating smaller declines in eGFR. Hazard ratios for the four interventions ranged from 0.63 to 0.82 for the endpoint incorporating 40% eGFR decline and 0.59 to 0.76 for the endpoint incorporating 57% eGFR decline. Clinical trials incorporating a 40% eGFR decline in a composite endpoint would require approximately half the number of participants compared to a 57% eGFR decline with equivalent statistical power. Thus, in populations at high risk of CKD progression, the relative effects of newer kidney protective therapies appear generally similar across endpoints based on varying eGFR decline thresholds.</p

Short-Term Changes in Albuminuria and Risk of Cardiovascular and Renal Outcomes in Type 2 Diabetes Mellitus:A Post Hoc Analysis of the EMPA-REG OUTCOME Trial

Background Early reduction in albuminuria with an SGLT2 (sodium-glucose cotransporter 2) inhibitor may be a positive indicator of long-term cardiovascular and renal benefits. We assessed changes in albuminuria during the first 12 weeks of treatment and subsequent long-term cardiovascular and renal risks associated with the SGLT2 inhibitor, empagliflozin, in the EMPA-REG OUTCOME (Empagliflozin Cardiovascular Outcome Event Trial in Type 2 diabetes Mellitus Patients) trial. Methods and Results We calculated the percentage urinary albumin creatinine ratio (UACR) change from baseline to week 12 in 6820 participants who did not experience a cardiovascular outcome (including 3-point major cardiovascular events and cardiovascular death or hospitalization for heart failure) or renal outcome (defined as 40% decline in estimated glomerular filtration rate from baseline, estimated glomerular filtration rate 30% reduction in UACR (odds ratio, 1.42; 95% CI, 1.27-1.58; P<0.001). During 3.0 years of follow-up, 704 major cardiovascular events, 440 cardiovascular deaths/hospitalizations for heart failure, and 168 renal outcomes were observed. Each 30% decrease in UACR during the first 12 weeks was statistically significantly associated with a lower hazard for major cardiovascular events (HR, 0.96; 95% CI, 0.93-0.99; P=0.012), cardiovascular deaths/hospitalizations for heart failure (HR, 0.94; 95% CI, 0.91-0.98; P=0.003), and renal outcomes (HR, 0.83; 95% CI, 0.78-0.89; P<0.001). Conclusions Short-term reduction in UACR was more common with empagliflozin and was statistically significantly associated with a decreased risk of long-term cardiovascular and renal outcomes. Registration URL: https://www.clinicaltrials.gov. Unique identifier: NCT01131676

Serum concentration of cystatin C and risk of end-stage renal disease in diabetes

OBJECTIVEdPatients with diabetes have a high risk of end-stage renal disease (ESRD). We examined whether prediction of this outcome, according to chronic kidney disease (CKD) staging by creatinine-based estimates of the glomerular filtration rate (eGFRcreat), is improved by further staging with serum cystatin C–based estimates (eGFRcyst). RESEARCH DESIGN AND METHODSdPatients with diabetes in CKD stages 1–3 were selected from three cohorts: two from Joslin Diabetes Center, one with type 1 diabetes (N = 364) and one with type 2 diabetes (N = 402), and the third from the Finnish Diabetic Nephropathy (FinnDiane) Study of type 1 (N = 399). Baseline serum concentrations of creatinine and cystatin C were measured in all patients. Follow-up averaged 8–10 years and onsets of ESRD (n = 246) and death unrelated to ESRD (n = 159) were ascertained. RESULTSdAlthough CKD staging by eGFRcyst was concordant with that by eGFRcreat for 62% of Joslin patients and 73% of FinnDiane patients, those given a higher stage by eGFRcyst than eGFRcreat had a significantly higher risk of ESRD than those with concordant staging in all three cohorts (hazard ratio 2.3 [95% CI 1.8–3.1]). Similarly, patients at a lower stage by eGFRcyst than by eGFRcreat had a lower risk than those with concordant staging (0.30 [0.13–0.68]). Deaths unrelated to ESRD followed the same pattern, but differences were not as large. CONCLUSIONSdIn patients with diabetes, CKD staging based on eGFRcyst significantly improves ESRD risk stratification based on eGFRcreat. This conclusion can be generalized to patients with type 1 and type 2 diabetes and to diabetic patients in the U.S. and Finland

Bardoxolone Methyl Improves Kidney Function in Patients with Chronic Kidney Disease Stage 4 and Type 2 Diabetes:Post-Hoc Analyses from Bardoxolone Methyl Evaluation in Patients with Chronic Kidney Disease and Type 2 Diabetes Study

Background: Increases in measured inulin clearance, measured creatinine clearance, and estimated glomerular filtration rate (eGFR) have been observed with bardoxolone methyl in 7 studies enrolling approximately 2,600 patients with type 2 diabetes (T2D) and chronic kidney disease (CKD). The largest of these studies was Bardoxolone Methyl Evaluation in Patients with Chronic Kidney Disease and Type 2 Diabetes (BEACON), a multinational, randomized, double-blind, placebo-controlled phase 3 trial which enrolled patients with T2D and CKD stage 4. The BEACON trial was terminated after preliminary analyses showed that patients randomized to bardoxolone methyl experienced significantly higher rates of heart failure events. We performed post-hoc analyses to characterize changes in kidney func-tion induced by bardoxolone methyl. Methods: Patients in -BEACON (n = 2,185) were randomized 1: 1 to receive oncedaily bardoxolone methyl (20 mg) or placebo. We compared the effects of bardoxolone methyl and placebo on a post-hoc composite renal endpoint consisting of = 30% decline from baseline in eGFR, eGFR <15 mL/min/1.73 m2, and end-stage renal disease (ESRD) events (provision of dialysis or kidney transplantation). Results: Consistent with prior studies, patients randomized to bardoxolone methyl experienced mean increases in eGFR that were sustained through study week 48. Moreover, increases in eGFR from baseline were sustained 4 weeks after cessation of treatment. Patients randomized to bardoxolone methyl were significantly less likely to experience the composite renal endpoint (hazards ratio 0.48 [95% CI 0.36-0.64]; p <0.0001). Conclusions: Bardoxolone methyl preserves kidney function and may delay the onset of ESRD in patients with T2D and stage 4 CKD. (C) 2018 The Author(s) Published by S. Karger AG, Base

Association of Treatment Effects on Early Change in Urine Protein and Treatment Effects on GFR Slope in IgA Nephropathy:An Individual Participant Meta-analysis

Rationale & Objective: An early change in proteinuria is considered a reasonably likely surrogate end point in immunoglobulin A nephropathy (IgAN) and can be used as a basis for accelerated approval of therapies, with verification in a postmarketing confirmatory trial. Glomerular filtration rate (GFR) slope is a recently validated surrogate end point for chronic kidney disease progression and may be considered as the end point used for verification. We undertook a metaanalysis of clinical trials in IgAN to compare treatment effects on change in proteinuria versus change in estimated GFR (eGFR) slope. Study Design: Individual patient-level metaanalysis. Setting & Study Populations: Individual data of 1,037 patients from 12 randomized trials. Selection Criteria for Studies: Randomized trials of IgAN with proteinuria measurements at baseline and 6 (range, 2.5-14) months and at least a further 1 year of follow-up for the clinical outcome. Analytical Approach: For each trial, we estimated the treatment effects on proteinuria and on the eGFR slope, computed as the total slope starting at baseline or the chronic slope starting 3 months after randomization. We used a Bayesian mixed-effects analysis to relate the treatment effects on proteinuria to effects on GFR slope across these studies and developed a prediction model for the treatment effect on the GFR slope based on the effect on proteinuria. Results: Across all studies, treatment effects on proteinuria accurately predicted treatment effects on the total slope at 3 years (median R-2 = 0.88; 95% Bayesian credible interval [BCI], 0.06-1) and on the chronic slope (R-2 = 0.98; 95% BCI, 0.29-1). For future trials, an observed treatment effect of approximately 30% reduction in proteinuria would confer probabilities of at least 90% for nonzero treatment benefits on the total and chronic slopes of eGFR. We obtained similar results for proteinuria at 9 and 12 months and total slope at 2 years. Limitations: Study population restricted to 12 trials of small sample size, leading to wide BCIs. There was heterogeneity among trials with respect to study design and interventions. Conclusions: These results provide new evidence supporting that early reduction in proteinuria can be used as a surrogate end point for studies of chronic kidney disease progression in IgAN

A New Panel-Estimated GFR, Including beta(2)-Microglobulin and beta-Trace Protein and Not Including Race, Developed in a Diverse Population

RATIONALE AND OBJECTIVE: GFR estimation based on creatinine and cystatin C (eGFR(cr-cys)) is more accurate than eGFR based on either creatinine or cystatin C alone (eGFR(cr) or eGFR(cys)), but the inclusion of creatinine in eGFR(cr-cys) requires specification of a person’s race. Beta-2-microglobulin (B2M) and beta-trace protein (BTP) are alternative filtration markers that appear to be less influenced by race than creatinine. STUDY DESIGN: Study of diagnostic test accuracy. SETTING AND PARTICIPANTS: Development in pooled population of seven studies with 5017 participants with and without chronic kidney disease. External validation in a pooled population of seven other studies with 2245 participants. TESTS COMPARED: Panel eGFR using B2M and BTP in addition to cystatin C (three-marker panel) or creatinine and cystatin C (four-marker panel) with and without age and sex or race. OUTCOMES: GFR measured as the urinary clearance of iothalamate, plasma clearance of iohexol, or plasma clearance of Cr-EDTA RESULTS: Mean measured GFR was 58.1 and 83.2 ml/min/1.73m(2) and the proportion of blacks was 38.6% and 24.0%, in the development and validation populations, respectively. In development, addition of age and sex improved the performance of all equations compared to equations without age and sex, but addition of race did not further improve the performance. In validation, the four-marker panels were more accurate than the three-marker panels (p<0.001). The three-marker panel without race was more accurate than eGFR(cys) [1- P(30) of 15.6 vs 17.4% (p=0.014)], and the four-marker panel without race was as accurate as eGFR(cr-cys) [1- P(30) of 8.6 vs 9.4% (p=0.17)]. Results were generally consistent across subgroups. LIMITATIONS: No representation of participants with severe comorbid illness and from geographic areas outside of North America and Europe. CONCLUSIONS: The four-marker panel eGFR is as accurate as eGFR(cr-cys), without requiring specification of race. A more accurate race-free eGFR could be an important advance

Accuracy of GFR estimating equations based on creatinine, cystatin C or both in routine care.

peer reviewed[en] 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

Early Change in Urine Protein as a Surrogate End Point in Studies of IgA Nephropathy: An Individual-Patient Meta-analysis

Background The role of change in proteinuria as a surrogate end point for randomized trials in immunoglobulin A nephropathy (IgAN) has previously not been thoroughly evaluated. Study Design Individual patient–level meta-analysis. Setting &amp; Population Individual-patient data for 830 patients from 11 randomized trials evaluating 4 intervention types (renin-angiotensin system [RAS] blockade, fish oil, immunosuppression, and steroids) examining associations between changes in urine protein and clinical end points at the individual and trial levels. Selection Criteria for Studies Randomized controlled trials of IgAN with measurements of proteinuria at baseline and a median of 9 (range, 5-12) months follow-up, with at least 1 further year of follow-up for the clinical outcome. Predictor 9-month change in proteinuria. Outcome Doubling of serum creatinine level, end-stage renal disease, or death. Results Early decline in proteinuria at 9 months was associated with lower risk for the clinical outcome (HR per 50% reduction in proteinuria, 0.40; 95% CI, 0.32-0.48) and was consistent across studies. Proportions of treatment effect on the clinical outcome explained by early decline in proteinuria were estimated at 11% (95% CI, −19% to 41%) for RAS blockade and 29% (95% CI, 6% to 53%) for steroid therapy. The direction of the pooled treatment effect on early change in proteinuria was in accord with the direction of the treatment effect on the clinical outcome for steroids and RAS blockade. Trial-level analyses estimated that the slope for the regression line for the association of treatment effects on the clinical end points and for the treatment effect on proteinuria was 2.15 (95% Bayesian credible interval, 0.10-4.32). Limitations Study population restricted to 11 trials, all having fewer than 200 patients each with a limited number of clinical events. Conclusions Results of this analysis offer novel evidence supporting the use of an early reduction in proteinuria as a surrogate end point for clinical end points in IgAN in selected settings