Meaningful Interpretation of Risk Reduction from Clinical Drug Trials

Abstract

OBJECTIVE: To illustrate the concepts of relative and absolute risk reduction, and by example, present and discuss the results of prevention trials that have evaluated the impact of drug therapy on cardiovascular disease. Additional approaches to evaluating the results of prevention trials are also presented. DATA SOURCES: Data were gathered from eight frequently quoted major cardiovascular intervention trials. CONCLUSIONS: Reference to large reductions in relative risk in review papers, newspapers, and at professional meetings can lead to false expectations among clinicians and patients regarding the potential impact of the treatment in individual patients. When making decisions about preventive drug therapy, clinicians are encouraged to examine measures other than relative risk reduction and to include the patient in the decision process. Educators should emphasize these other measures of outcome and not rely solely on relative risk reduction in discussing particular areas of therapeutics.