OBJECTIVES : To describe the real-world antipsychotic (AP) treatment discontinuation patterns and the association between treatment discontinuation and healthcare costs among bipolar disorder patients.

METHODS : A retrospective observational study was conducted using administrative claims data the IBM® MarketScan Commercial Database. Patients with at least 1 medical claim with a diagnosis of bipolar disorder (manic or mixed sub-type) and newly initiating AP therapy between 1/1/11-6/30/16 were included. Baseline patient characteristics were assessed in the 12 months prior to the AP initiation. Total healthcare costs and healthcare utilization were assessed during a 24-month follow-up. Discontinuation of index AP therapy, defined as a gap of at least 60 days without the medication on-hand, was utilized as a predictor of healthcare costs and utilization outcomes in generalized linear and logistic regression models adjusted for baseline characteristics. Predictors of discontinuation were also assessed via logistic regression.

RESULTS : A total of 18,259 bipolar disorder patients were identified as new initiators of APs. The cohort was 61% female and had an average age of 39 years. The most commonly initiated AP was quetiapine (33.6%), followed by aripiprazole (29.3%). A total of 15,460 patients (85%) discontinued their index regimen. Patients with baseline substance use disorders, depression, and other anxiety disorders were significantly more likely to discontinue. More than half of the cohort utilized emergency room services (53%) and 33% had at least one inpatient admission during the follow-up. The median total healthcare costs were $24,861 during the 24-month follow-up. Controlling for differences in baseline characteristics, discontinuation of AP therapy was associated with 24% higher total healthcare costs (Cost ratio: 1.24; p<0.001) and 33% higher inpatient+ER costs (1.33; p<0.001).

CONCLUSIONS : Discontinuation of AP therapy among bipolar disorder patients is high and contributes to excess healthcare costs and high-cost services. Future research focusing on the reasons for discontinuation may inform medication adherence initiatives.