The Application of the Principle of Intention–to–Treat to the Analysis of Clinical Trials

Abstract

A chronology of populations of patients eligible for analysis in clinical trials is discussed. A practical definition of the intention–to–treat population is given and its role relative to the efficacy analyzable population discussed for both parallel groups and crossover trials. Sensitivity analyses are proposed to address dilemmas as to which population of patients is appropriate for the final analysis of the trial. Associated issues regarding multiple comparisons, exclusion analyses, and post hoc analyses are discussed in the context of the intention–to–treat approach to statistical analysis. Examples for analgesia, intermittent claudication, anxiety or depression, and duodenal ulcers are given to illustrate the points discussed.