Patterns of atypical antipsychotic therapy use in adults with bipolar I disorder in the USA.

Objectives: This study aims to describe the utilization patterns of atypical antipsychotics (AA) among insured patients with bipolar I disorder in the USA.

Methods: We studied patients with bipolar I disorder who newly initiated an oral AA between 2002 and 2008. Utilization measures included adherence [medication possession ratio (MPR) ≥80%], persistence (gaps ≤15 days between refills and an absence of ≥30 days of continuous concomitant non-index AA use), non-compliance (16-29 day gaps with no evidence of switch/augmentation), and discontinuation of the index AA (≥30 days without index AA, no evidence of switch/augmentation).

Results: The study included 16 807 patients: mean age 43.3 years, 67.7% female. Overall, adherence to the index AA was low (8.3%; mean MPR = 0.2). Only 10.5% of the patients were persistent to index AA, another 13.6% were non-compliant, and 63.4% discontinued index AA with an average time to discontinuation of 66 days. A majority (69.5%) of the discontinued patients did not resume any antipsychotic therapy. Results were similar across insurance types and index AA.

Conclusion: Adherence to and persistence with AA treatment were low in new users with bipolar I disorder. Most patients discontinued the index AA and did not restart any antipsychotic treatment. Future study should distinguish physician-directed discontinuation versus patient non-adherence.