Impact of transdermal drug delivery on treatment adherence in patients with Alzheimer's disease.

Objective: As a part of a study investigating which strategies are effective to improve pharmacological compliance among nonadherent Alzheimer's disease patients, we assessed the impact of the galenic form (oral medications or patches) on treatment adherence in patients with dementia of Alzheimer's type (DAT).

Design And Methods: We performed a 6-month prospective, multicenter, observational study with three study visits (baseline, 3 months and 6 months). Patients with mild-to-moderately severe DAT receiving medication for ≥3 months who were nonadherent to treatment were recruited.

Outcome Measures: The main variable was adherence rate recorded at each visit. Patients were adherent if they missed <20% of the doses of their medication and they took it at the dose, manner and timing prescribed by the physician >80% of times. Secondary variables included strategies followed by physicians to improve adherence and reasons for nonadherence reported by patients.

Results: A total of 649 patients (35.2% men) were included. The percentage of adherent patients reached 73.6% at 3 months and rose to 85.9% at 6 months. The most common reasons for nonadherence were forgetfulness, avoidance of adverse events and refusal of treatment. Modification of treatment was the most frequent strategy followed by physicians for improving treatment adherence at baseline, and the only intervention that substantially improved adherence at the 3-month visit (the percentage of patients treated with patches increased from 6.1% at baseline to 64.8% at 3-month visit). Patients using patches were more likely to comply than patients using capsules/tablets, as demonstrated by logistic regression analysis.

Conclusions: The results suggested that the transdermal patch may improve adherence, which may lead to an increase of treatment benefits in patients with DAT.