Different eGFR Decline Thresholds and Renal Effects of Canagliflozin: Data from the CANVAS Program

BACKGROUND: Traditionally, clinical trials evaluating effects of a new therapy with creatinine-based renal end points use doubling of serum creatinine (equivalent to a 57% eGFR reduction), requiring large sample sizes.METHODS: To assess whether eGFR declines RESULTS: Among the 10,142 participants, 93 (0.9%), 161 (1.6%), 352 (3.5%), and 800 (7.9%) participants recorded renal outcomes on the basis of 57%, 50%, 40%, or 30% eGFR reduction, respectively, during a mean follow-up of 188 weeks. Compared with a 57% eGFR reduction (risk ratio [RR], 0.51; 95% confidence interval [95% CI], 0.34 to 0.77), the effect sizes were progressively attenuated when using 50% (RR, 0.61; 95% CI, 0.45 to 0.83), 40% (RR, 0.70; 95% CI, 0.57 to 0.86), or 30% (RR, 0.81; 95% CI, 0.71 to 0.93) eGFR reductions. In analyses that controlled for the acute hemodynamic fall in eGFR, effect sizes were comparable, regardless of whether a 57%, 50%, 40%, or 30% eGFR reduction was used. Estimated sample sizes for studies on the basis of lesser eGFR reductions were much reduced by controlling for this early hemodynamic effect.CONCLUSIONS: Declines in eGFR CLINICAL TRIAL REGISTRY NAME AND REGISTRATION NUMBER: CANagliflozin cardioVascular Assessment Study (CANVAS), NCT01032629 and CANVAS-R, NCT01989754.