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.