title: Similar, the same or just not different: a guide for deciding whether treatments are clinically equivalent. [Dept. of Medicine, Division of Cardiology, Univ. of Western Ontario, London, Ontario].
abstract: Most clinical trials are designed to demonstrate superiority of one intervention over another. A less common goal is to show that any differences are sufficiently small to consider them interchangeable or clinically equivalent. Although similar to effectiveness trials, equivalence trials pose distinct methodological and interpretive challenges. Emphasis is placed on the distinction between a study designed to show 'equivalence' and a study designed to show 'superiority' that fails in its quest but in the end claims equivalence. Strategies used to minimize bias in superiority trials may actually increase the probability of showing no difference. Although there is no consensus as to the best statistical approach in describing the results of equivalence trials, an approach based on confidence intervals may be easier for clinicians to comprehend. A guide was developed to assist readers in determining whether claims of clinical equivalence are valid.
authors.affiliation: The University of Western Ontario, London, Canada. dmassel@lhsc.on.ca
authors.forename: D
authors.initials: D
authors.lastname: Massel
mesh_terms: D002318:Cardiovascular Diseases / Q000628:therapy*; D002986:Clinical Trials as Topic; D016001:Confidence Intervals; D006801:Humans; D013810:Therapeutic Equivalency; D016896:Treatment Outcome