Choosing primary endpoints for clinical trials of health care interventions.

The purpose of late phase clinical trials is to generate evidence of sufficient validity and generalisability to be translated into practice and policy to improve health outcomes. It is therefore crucial that the chosen endpoints are meaningful to the clinicians, patients and policymakers that are the end-users of evidence generated by these trials. The choice of endpoints may be improved by understanding their characteristics and properties. This narrative review describes the evolution, range and relative strengths and weaknesses of endpoints used in late phase trials. It is intended to serve as a reference to assist those designing trials when choosing primary endpoint(s), and for the end-users charged with interpreting these trials to inform practice and policy.