Correcting for non-compliance in randomized trials: an application to the ATBC study

✍ Scribed by Pasi A. Korhonen; Nan M. Laird; Juni Palmgren

• Publisher: John Wiley and Sons
• Year: 1999
• Tongue: English
• Weight: 171 KB
• Volume: 18
• Category: Article
• ISSN: 0277-6715
• DOI: 10.1002/(sici)1097-0258(19991115)18:21<2879::aid-sim190>3.0.co;2-k

✦ Synopsis

Di!erent methods for estimating the e!ect of treatment actually received in a longitudinal placebocontrolled trial with non-compliance are discussed. Total mortality from the ATBC Study is used as an illustrative example. In the ATBC Study some 25 per cent of the participants dropped out from active follow-up prior to the scheduled end of the study. The &intention-to-treat' analysis showed an increased death risk in the beta-carotene arm when compared with the no beta-carotene arm. Owing to considerable non-compliance it is also of interest to estimate the e!ect of beta-carotene actually received. We use a simple model for the treatment action and discuss three methods for estimation of the treatment e!ect under the model } the &intention-to-treat' approach, the &as-treated' approach and the g-estimation approach. These approaches are compared in a simulation study under di!erent settings for non-compliance. Finally, the data from the ATBC Study are analysed using the proposed methods.