Role of patient experience in atypical antipsychotic adherence: a retrospective data analysis.

Objective: We report on differences in atypical antipsychotic adherence after the start of outpatient treatment with atypical antipsychotics in patients receiving routine clinical care, based on whether they had been dispensed antipsychotic medication during the previous 180 days. We hypothesized that prior receipt of an antipsychotic prescription would identify patients with a reduced risk for medication discontinuation, perhaps due to greater experience with illness and/or medication experience.

Methods: De-identified computerized pharmacy records of 406,032 patients from 1157 pharmacies throughout the United States were used to select patients who were dispensed a noninjectable atypical antipsychotic between October 1, 2003, and March 31, 2004. Patients receiving an atypical antipsychotic prescription during this enrollment period were divided into 2 groups. One group consisted of patients to whom antipsychotic medications had been dispensed in the 180-day period prior to the index outpatient fill. The other group was composed of individuals who had not been dispensed a conventional or atypical antipsychotic during this period. Adherence was measured using Kaplan-Meier time-to-discontinuation analysis during a 360-day follow up period after the enrollment date. Discontinuation was defined as being 30 days late for a scheduled refill.

Results: Patients without receipt of an antipsychotic in the 180-day period prior to the index fill composed 32.6% of the total sample of patients (N = 406,432). Women composed 55.2% of the sample; men, 44.8%. The mean age was 43.7 years. In patients previously dispensed an antipsychotic medication, the median time to discontinuation was 125 days, while in patients not previously dispensed an antipsychotic medication, this value was 34 days.

Conclusions: In this analysis of data from pharmacy records, past antipsychotic use appeared to be associated with atypical antipsychotic adherence. Patients without evidence of having been dispensed antipsychotic medication during the 180 days prior to the index antipsychotic prescription appeared to have a high risk for medication discontinuation in the first 30 days after the start of outpatient therapy. This finding suggests that close follow-up during that period in patients who are either new to antipsychotic medication or who are being restarted on an antipsychotic after a prolonged lapse in use may be beneficial.