The US Food and Drug Administration (FDA) and European Medicines Agency (EMA) are currently willing to consider a 30% to 40% glomerular filtration rate (GFR) decline as a surrogate end point for kidney failure for clinical trials of kidney disease progression under appropriate conditions. However, these end points may not be practical for early stages of kidney disease. In March 2018, the National Kidney Foundation sponsored a scientific workshop in collaboration with the FDA and EMA to evaluate changes in albuminuria or GFR as candidate surrogate end points. Three parallel efforts were presented: meta-analyses of observational studies (cohorts), meta-analyses of clinical trials, and simulations of trial design. In cohorts, after accounting for measurement error, relationships between change in urinary albumin-creatinine ratio (UACR) or estimated GFR (eGFR) slope and the clinical outcome of kidney disease progression were strong and consistent. In trials, the posterior median R 2 of treatment effects on the candidate surrogates with the clinical outcome was 0.47 (95% Bayesian credible interval [BCI], 0.02-0.96) for early change in UACR and 0.72 (95% BCI, 0.05-0.99) when restricted to baseline UACR > 30 mg/g, and 0.97 (95% BCI, 0.78-1.00) for total eGFR slope at 3 years and 0.96 (95% BCI, 0.63-1.00) for chronic eGFR slope (ie, the slope excluding the first 3 months from baseline, when there might be acute changes in eGFR). The magnitude of the relationships of changes in the candidate surrogates with risk for clinical outcome was consistent across cohorts and trials: a UACR reduction of 30% or eGFR slope reduction by 0.5 to 1.0 mL/min/1.73 m 2 per year were associated with an HR of w0.7 for the clinical outcome in cohorts and trials. In simulations, using GFR slope as an end point substantially reduced the required sample size and duration of follow-up compared with the clinical end point when baseline eGFR was high, treatment effects were uniform, and there was no acute effect of the treatment. We conclude that both early change in albuminuria and GFR slope fulfill criteria for surrogacy for use as end points in clinical trials for chronic kidney disease progression under certain conditions, with stronger support for change in GFR than albuminuria. Implementation requires understanding conditions under which each surrogate is likely to perform well and restricting its use to those settings. Complete author and article information provided before references.

Outpatient potassium levels both above and below the normal range are consistently associated with adverse outcomes, with similar risk relationships across eGFR and albuminuria.

The effect of intensive glucose control on major kidney outcomes in type 2 diabetes remains unclear. To study this, the ADVANCE trial randomly assigned 11,140 participants to an intensive glucose-lowering strategy (hemoglobin A1c target 6.5% or less) or standard glucose control. Treatment effects on end-stage renal disease ((ESRD), requirement for dialysis or renal transplantation), total kidney events, renal death, doubling of creatinine to above 200 μmol/l, new-onset macroalbuminuria or microalbuminuria, and progression or regression of albuminuria, were then assessed. After a median of 5 years, the mean hemoglobin A1c level was 6.5% in the intensive group, and 7.3% in the standard group. Intensive glucose control significantly reduced the risk of ESRD by 65% (20 compared to 7 events), microalbuminuria by 9% (1298 compared to 1410 patients), and macroalbuminuria by 30% (162 compared to 231 patients). The progression of albuminuria was significantly reduced by 10% and its regression significantly increased by 15%. The results were almost identical in analyses taking account of potential competing risks. The number of participants needed to treat over 5 years to prevent one ESRD event ranged from 410 in the overall study to 41 participants with macroalbuminuria at baseline. Thus, improved glucose control will improve major kidney outcomes in patients with type 2 diabetes.

Aim The use of sodium glucose co‐transporter 2 (SGLT2) inhibitors in patients with type 2 diabetes mellitus (T2DM) and chronic kidney disease (CKD) has been limited, primarily because glycaemic efficacy is dependent on kidney function. We performed a systematic review and meta‐analysis to assess the efficacy and safety of SGLT2 inhibitors in patients with T2DM and CKD, defined as estimated glomerular filtration rate (eGFR) <60 mL/min/1.73 m2. Materials and methods We searched MEDLINE, EMBASE and the Cochrane Library until 7 August 2018 and websites of the US, European and Japanese regulatory authorities until 27 July 2018 for data from randomized controlled trials of SGLT2 inhibitors that included reporting of effects on biomarkers, cardiovascular, renal or safety outcomes in individuals with T2DM and CKD. Random effects models and inverse variance weighting were used to calculate relative risks with 95% confidence intervals. Results Data were obtained from 27 studies with up to 7363 participants involved. In patients with T2DM and CKD, SGLT2 inhibitors lowered glycated haemoglobin (−0.29%; 95% CI, −0.39 to −0.19) as well as blood pressure, body weight and albuminuria. SGLT2 inhibition reduced the risk of cardiovascular death, nonfatal myocardial infarction or nonfatal stroke (RR, 0.81; 95% CI, 0.70‐0.94) and heart failure (RR, 0.61; 95% CI, 0.48‐0.78), without a clear effect on all‐cause mortality (HR, 0.86; 95% CI, 0.73‐1.01). These agents also attenuated the annual decline in eGFR slope (placebo‐subtracted difference of 1.35 mL/1.73 m2/y; 95% CI, 0.78‐1.93) and reduced the risk of the composite renal outcome (HR, 0.71; 95% CI, 0.53‐0.95). There was no evidence of additional risks with SGLT2 inhibition in CKD beyond those already known for the class, although heterogeneity was observed across individual agents for some safety outcomes. Conclusion Currently available data suggest that, despite only modest reductions in glycated haemoglobin, SGLT2 inhibitors reduce the risk of cardiovascular and renal outcomes in patients with T2DM and CKD, without clear evidence of additional safety concerns.