Developing, Analyzing, and Interpreting Outcome Assessments to Improve Endpoints in Infectious Diseases Clinical Research.

Evidence from clinical research studies, in addition to patient values and clinical experience, helps practitioners best apply medical interventions to clinical practice. Part of evaluating the evidence is understanding the outcomes used as endpoints in research studies. The most direct evidence of patient benefit comes from endpoints that evaluate the effects of interventions on patient survival, symptoms, and function, and the impact of symptoms and function on health-related quality of life. In this article, we discuss how to develop endpoints for clinical research studies focusing on patient-reported outcome measures, including those measuring patient symptoms, function, and health-related quality of life. We discuss the process for determining (1) which concepts to measure, including which concepts are most relevant to patients (content validity); (2) who performs the measurement and which measurement properties to use (construct validity); and (3) how to analyze and interpret the results obtained using the chosen measurements.