Pharmacoepidemiology and Drug Safety | 2019
Analyzing patient‐reported outcome data when completion differs between arms in open‐label trials: an application of principal stratification
Abstract
Cancer trials are often open‐label and include patient‐reported outcomes (PROs). Previous work has demonstrated that patients may complete PRO assessments less frequently in the control arm compared with the experimental arm in open‐label trials. Such differential completion may affect PRO results. This paper sought to explore principal stratification methodology to address potential bias caused by the posttreatment intermediate variable of questionnaire completion.