One-year costs of second-line therapies for depression

Background: We compared patterns of medical resource utilization and costs among patients receiving a serotonin-norepinephrine reuptake inhibitor (venlafaxine), one of the selective serotonin reuptake inhibitors (SSRIs), one of the tricyclic agents (TCAs), or 1 of 3 other second-line therapies for depression. Method: Using claims data from a national managed care organization, we identified patients diagnosed with depression (ICD-9-CM criteria) who received second-line antidepressant therapy between 1993 and 1997. Second-line therapy was defined as a switch from the first class of antidepressant therapy observed in the data set within 1 year of a diagnosis of depression to a different class of antidepressant therapy. Patients with psychiatric comorbidities were excluded. Results: Of 981 patients included in the study, 21% (N = 208) received venlafaxine, 34% (N = 332) received an SSRI, 19% (N = 191) received a TCA, and 25% (N = 250) received other second- line antidepressant therapy. Mean age was 43 years, and 72% of patients were women. Age, prescriber of second-line therapy, and prior 6-month expenditures all differed significantly among the 4 therapy groups. Total, depression- coded, and non-depression-coded 1-year expenditures were, respectively, $6945, $2064, and $4881 for venlafaxine; $7237, $1682, and $5555 for SSRIs; $7925, $1335, and $6590 for TCAs; and $7371, $2222, and $5149 for other antidepressants. In bivariate analyses, compared with TCA-treated patients, venlafaxine- and SSRI-treated patients had significantly higher depression- coded but significantly lower non-depression-coded expenditures. Venlafaxine was associated with significantly higher depression-coded expenditures than SSRIs. However, after adjustment for potential confounding covariables in multivariate analyses, only the difference in depression-coded expenditures between SSRI and TCA therapy remained significant. Conclusion: After adjustment for confounding patient characteristics, 1-year medical expenditures were generally similar among patients receiving venlafaxine, SSRIs, TCAs, and other second-line therapies for depression. Observed differences in patient characteristics and unadjusted expenditures raise questions as to how different types of patients are selected to receive alternative second-line therapies for depression.