How should we deal with missing data in clinical trials involving Alzheimer's disease patients?

Missing data are frequent in Alzheimer's disease (AD) trials due to the age of participants and the nature of the disease. This can lead to bias and decreased statistical power. We assessed the level and causes of missing data in a 2-year randomised trial of an AD patient management program (PLASA study), and conducted sensitivity analyses on the primary endpoint (functional decline), using various methods for handling missing data: complete case, LOCF, Z-score LOCF, longitudinal mixed effects model, multiple imputation.