Differences in total medical costs across the SSRIs for the treatment of depression and anxiety.

There is growing evidence that adherence to the recommended duration of antidepressant therapy results in reduced medical costs compared with nonadherence, and that the likelihood of adhering to therapy is not equivalent across the selective serotonin reuptake inhibitors (SSRIs). As such, the purpose of this study was to assess differences in 6-month medical costs between paroxetine controlled-release (CR) and immediate-release (IR) SSRI agents in a retrospective analysis of patients initiating SSRI therapy identified from the Integrated Healthcare Information Services National Managed Care Benchmark Database during a 2.5-year time frame. Inferential analyses were performed to evaluate differences in 6-month medical costs, controlling for differences in age, sex, utilization of psychiatric specialty care services, titration, pre-period costs, and comorbidity measures. Of the 146 075 patients included in this study, approximately 7% received paroxetine CR. Approximately 29.5% of patients had an anxiety disorder diagnosis; 26.0% had a depression-only diagnosis; and 13.2% had comorbid anxiety and depression. The 6-month medical costs were 244 US dollars lower for patients initiating with paroxetine CR compared with the average medical costs for patients receiving IR SSRIs. Paroxetine CR also had the lowest medical costs compared with each individual SSRI evaluated. After log transformation of costs and adjustment for baseline covariates, the aggregated IR SSRIs were associated with 8.7% higher 6-month medical costs than paroxetine CR (P <.001) and even greater costs after stratifying by diagnosis: 12.5% higher costs in patients with anxiety, 14.3% higher costs in patients with depression, and 15.9% higher costs in patients with comorbid anxiety and depression (P <.001 for all). Each individual IR SSRI was also associated with significantly higher medical costs than paroxetine CR, irrespective of diagnosis. As demonstrated, medical costs over a 6-month time frame were significantly greater for IR SSRIs versus paroxetine CR, even after adjusting for background characteristics and stratifying by diagnosis. Future studies should measure rates of adherence in relation to medical outcomes over an expanded time frame.