[Costs and associated factors with optimal and suboptimal responses to the treatment of major depressive disorder].

Objective: To evaluate the compliance, persistence and costs of the treatment of major depressive disorder (MDD) in the setting of Primary Care, placing emphasis on the different aspects of those patients with an initial suboptimal response to antidepressant treatment.

Design: A retrospective observational study using the population registers of Badalona Healthcare Services. The inclusion criteria consisted of; age ≥18 years, initial episode during 2008-2009, and to be on antidepressant treatment for at least 8 weeks after the first prescription. The follow-up was 12 months. Two study groups were formed, patients with suboptimal response, and remission.

Main Measurements: Sociodemographic data, compliance and adherence to treatment, health costs (direct and indirect).

Results: A total of 2,260 subjects were analysed (mean age 58.8 years, 74% women). Just under half (42.7%, 95% CI; 40.0-46.4%) had a suboptimal response to the treatment. These patients had a higher mean age, a higher proportion of women, and pensioners, as well as higher comorbidity, compared to the remission group. They also had poorer compliance percentages (65.1% vs. 67.7%) and treatment persistence at 12 months (31.8% vs. 53.2%), respectively, P<.001. The annual health costs were, 826.1€ for patients with a suboptimal response vs. 451.2€ in patients in remission; loss of productivity 1,842.0€ vs. 991.4€, respectively; P<.001. The factors associated to a suboptimal response were; lack of compliance (OR=1.7), years with the disorder (OR=1.2), age (OR=1.1) and presence of comorbidity (OR=1.1).

Conclusions: The patients with an initial suboptimal response to antidepressant treatment had a higher comorbidity, lower therapeutic compliance, and incurred higher total costs, particularly in losses in work productivity.