Differences in medication use in the Alzheimer's disease neuroimaging initiative: analysis of baseline characteristics.

The ADNI (Alzheimer's Disease Neuroimaging Initiative) is a large longitudinal study of patients with probable Alzheimer's disease (AD), patients with mild cognitive impairment (MCI) and healthy elderly controls followed for at least 2-3 years. Many participants in the ADNI are being treated with medications, and these may have beneficial or deleterious effects. The goal of the study was to characterize baseline medication use in the ADNI. Diagnosis, demographics, medication status, psychometric data and MRI measures of hippocampal volume and entorhinal cortex thickness were obtained for 818 participants from the ADNI cohort. Total number of medications, Beers list (potentially dangerous) medications and AD treatments were also tabulated. ANOVA and logistic regression were used to assess associations between baseline pharmacotherapy and diagnosis, demographics, and selected clinical and MRI variables. Of the 818 enrolled ADNI participants, 809 were available for analysis in the present study, including 184 patients with AD, 399 patients with MCI and 226 healthy elderly controls. Significant gender differences in recruitment were observed in the MCI group. The average number of medications per participant was 8 (SD 4) and 22% reported treatment with one or more Beers list medications. For symptomatic treatment of MCI or AD, donepezil and memantine were the most commonly reported drugs. As expected, MCI and AD patients with more severe impairment were more likely to be treated. Men received treatment more frequently than women. Older subjects and those with less education were less likely to receive treatment. AD and MCI participants from the ADNI cohort were being treated with polypharmacy and many were also taking one or more medications with the potential for adverse effects. Off-label use of cholinesterase inhibitors and/or memantine for MCI was common, with more severely affected patients most likely to receive treatment. Differences in the frequency of symptomatic treatment were also observed as a function of age, years of education, gender and disease severity.