OBJECTIVE: To assess “real world” drug persistence patterns for patients with Alzheimer’s Disease (AD) treated with clinically effective doses of rivastigmine or donepezil by evaluating rates of discontinuation and change in therapy. METHODS: A retrospective cohort study was conducted using longitudinal pharmacy claims data from the PharMetrics Patient-Centric database. Newly treated, US, community-based AD patients were identified as having an initial prescription (index event) for rivastigmine or donepezil between June and December, 2000. Patients receiving either drug during the 180 days prior to their index prescription or who did not have continuous plan enrollment during this period were excluded. Patients reaching clinically effective doses of donepezil (5..C10mg/day) or rivastigmine (6..C12 mg/day), and undergoing = 60 days continuous therapy were analyzed. The primary outcome measure was time to treatment failure, defined as either discontinuation of therapy (no prescription refill within 90 days of estimated completion of prior prescription) or switch to alternative AD drug. Kaplan-Meier survival and proportional hazard model analyses were performed. RESULTS: A total of 1650 AD patients treated with rivastigmine or donepezil met all study eligibility criteria and reached clinically effective doses. Treatment failure occurred for 66% of donepezil patients (27% within first 60 days) and 60% of rivastigmine patients (20% within first 60 days) during the approximate 1-year follow-up. The mean (95% CI) time to failure was 360 (332..C398) days for the rivastigmine group versus 376 (361..C391) days for donepezil (p = 0.083). In patients receiving the maximum recommended doses, mean time to treatment failure was 392 (372..C412) days with donepezil 10 mg/day versus 403 (352..C454) days for rivastigmine 12 mg/day (p = 0.24). CONCLUSIONS: Drug persistence patterns were similar for rivastigmine and donepezil patients who reach a clinically effective dose, but there was a trend in favor of rivastigmine for patients reaching higher doses.
