Among the several variables assessed, being male, >or=86 years of age, having a greater overall daily pill burden, or using a lower formulary tier AD medication was associated with better adherence to oral AD medication in patients diagnosed with AD. The database had no information on caregiver support, medication management interventions, or use of adherence aids that may have affected adherence in this cohort, yet, a substantial proportion of patients (42%) remained non-adherent. A better understanding of the causes of non-adherence is necessary, and methods to improve adherence, such as transdermal medications and educational programs, should be considered.