Background: Over the past decade, studies of the effectiveness of pharmacological treatment for depression have often been based on research designs intended to measure efficacy, and for this reason the results are of limited generalizability. Research is needed comparing the clinical and economic outcomes of antidepressants in day-to-day clinical practice.
Methods: A six-month randomised prospective naturalistic study comparing fluoxetine to imipramine carried out in three primary care health centres. Outcome measures were the Montgomery Asberg Depression Rating Scale (MADRS), direct costs, indirect costs and total costs. Subjects were evaluated at the beginning of treatment and at one, three and six months thereafter.
Results: Of the 103 patients, 38.8% (n = 40) were diagnosed with major depressive disorder, 14.6% (n = 15) with dysthymic disorder, and 46.6% (n = 48) with depressive disorder not otherwise specified. Patients with major depressive disorder or dysthymic disorder achieved similar clinical improvement in both treatment groups (mean MADRS ratings decrease in major depressive disorder from baseline to 6 months of 18.3 for imipramine and 18.8 for fluoxetine). For patients with major depressive disorder and dysthymic disorder, the imipramine group had fewer treatment-associated costs (imipramine 469.66 Euro versus fluoxetine 1,585.93 Euro in major depressive disorder, p < 0.05; imipramine 175.39 Euro versus fluoxetine 2,929.36 Euro in dysthymic disorder, p < 0.05). The group with depressive disorder not otherwise specified did not experience statistically significant differences in clinical and costs outcomes between treatment groups.
Limitations: Exclusion criteria, participating physicians may not represent GPs.
Conclusions: In a primary care context, imipramine may represent a more cost-effective treatment option than fluoxetine for treating major depressive disorder or dysthymic disorder. There were no differences in cost-effectiveness in the treatment of depressive disorder not otherwise specified.