Author Affiliations: Departments of Health Policy Management and Evaluation and Medicine, University of Toronto (Drs Tomlinson and Detsky); and Department of Medicine, Mount Sinai Hospital, and University Health Network (Drs Tomlinson and Detsky), Toronto, Ontario, Canada.
An article reporting the results of a randomized trial contained the following sentence: “This large, prospective, blinded international clinical trial shows that 8 mg of rosiglitazone daily, together with lifestyle recommendations, substantially reduces the risk of diabetes or death by 60% in individuals at high risk for diabetes.”1 Taken alone, this statement offers little guidance to a clinician who is prescribing the drug, because death and diabetes are quite far apart in the spectrum of severity. Two questions arise: Was there a 60% reduction in both death and diabetes? Are the two outcomes just as likely to occur? To make a decision, a clinician needs more information on the individual components, and the article in question does indeed provide this information. But after reading the entire report, the clinician may ask a third question: Why did the clinical trial use the primary outcome of diabetes or death?
Tomlinson G, Detsky AS. Composite End Points in Randomized TrialsThere Is No Free Lunch. JAMA. 2010;303(3):267-268. doi:10.1001/jama.2009.2017