Intent-to-treat analysis of health care expenditures of patients treated with atypical antipsychotics as adjunctive therapy in depression

Objective To compare health care utilization and expenditures in patients with depression whose initial antidepressant (AD) treatment was augmented with a second-generation antipsychotic. Methods Claims data from January 1, 2001, through June 30, 2009, were used to select patients aged 18 to 64 years with depression treated with ADs augmented with aripiprazole, olanzapine, or quetiapine. Patients were required to have 6 months of continuous eligibility before the first AD prescription and 6 months after the second-generation antipsychotic augmentation (index) date. Utilization and expenditures were assessed for 6 months after the index date. Multivariate regression was used to estimate adjusted expenditures and risks for hospitalizations and emergency department visits. Results A total of 483 patients treated with aripiprazole, 978 with olanzapine, and 2471 with quetiapine were selected. Mean adjusted expenditures for aripiprazole were significantly lower than those for olanzapine for each service category (all-cause, all-cause medical care, mental health-related, and mental health-related medical care) and were significantly lower than those for quetiapine for each category with the exception of mental health-related. The adjusted risks for hospitalization and emergency department visits were significantly higher for quetiapine than for aripiprazole. Conclusions Compared with patients treated with ADs and aripiprazole, those treated with ADs and olanzapine or quetiapine had greater utilization and higher expenditures.