Estimated GFR Decline as a Surrogate End Point for Kidney Failure: A Post Hoc Analysis From the Reduction of End Points in Non-Insulin-Dependent Diabetes With the Angiotensin II Antagonist Losartan (RENAAL) Study and Irbesartan Diabetic Nephropathy Trial

Despite increases in precision of the treatment effect, eGFR declines less than a doubling of serum creatinine value did not consistently improve statistical power of the clinical trials due to attenuation of the treatment effect. Attenuation of the treatment effect appears to be due in part to acute effects of ARBs on eGFR. These findings should be taken into account when using lesser eGFR declines as alternative end points for clinical trials.