Proteinuria should be used as a surrogate in CKD.

Surrogate end points of renal failure are instrumental to the testing of new treatments in patients with chronic kidney disease, the natural history of which is characterized by a slow, asymptomatic decline in renal function. The magnitude of proteinuria is widely recognized as a marker of the severity of glomerulopathy. Population-based studies have identified proteinuria as a predictor of future decline in glomerular filtration rate and of the development of end-stage renal disease. More importantly, a reduction in proteinuria invariably translates into a protection from renal function decline in patients with diabetic and nondiabetic renal disease with overt proteinuria. Thus, proteinuria should be considered a valuable surrogate end point for clinical trials in patients with proteinuric renal diseases.