Clinical Trials

■■❚❙❘Chapter 22Intention-to-TreatAnalysisDuolao Wang and Ameet BakhaiIn a clinical trial, the presentation of the results is a keyevent that can have many implications. Therefore, it is ofcritical importance to know whether these results have beengenerated using data from all subjects (intention-to-treat[ITT] analysis) or only from the subjects who adhered fullyto their assigned treatment protocol (per-protocol analysis).Between randomization and completion of the trial, subjectsmay stop being compliant, switch treatments unexpectedly,or withdraw from the study. Excluding data from such subjects(even if these data are incomplete) can result in bias. Therefore,an ITT analysis is more informative and gives results that arecloser to those that would be seen if the treatments were givento the population as a whole. In this chapter, we review theadvantages and limitations of an ITT strategy for compilingclinical trial results.255