Composite Primary Outcomes in Nephrology Clinical Trials

Composite study endpoints have made it possible to reduce the sample size and lower the cost of certain clinical trials. In nephrology trials, the use of composite endpoints has led to opportunities but has also created challenges in the interpretation of study results. In this perspective, we review how composite outcomes work and why there are risks attendant to their use. We also provide examples of the use of composite outcomes from specific nephrology trials and certain problems that resulted.