title: Informative noncompliance in endpoint trials.
abstract: Noncompliance with study medications is an important issue in the design of endpoint clinical trials. Including noncompliant patient data in an intention-to-treat analysis could seriously decrease study power. Standard methods for calculating sample size account for noncompliance, but all assume that noncompliance is noninformative, i.e., that the risk of discontinuation is independent of the risk of experiencing a study endpoint. Using data from several published clinical trials (OPTIMAAL, LIFE, RENAAL, SOLVD-Prevention and SOLVD-Treatment), we demonstrate that this assumption is often untrue, and we discuss the effect of informative noncompliance on power and sample size.
authors.affiliation: Steven Snapinn, Amgen, One Amgen Center Drive 24-2-C, Thousand Oaks CA 91320 USA. ssnapinn@amgen.com
authors.forename: Steven M
authors.initials: SM
authors.lastname: Snapinn
authors.forename: Qi
authors.initials: Q
authors.lastname: Jiang
authors.forename: Boris
authors.initials: B
authors.lastname: Iglewicz