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

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

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).

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.

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.