Results of a Retrospective Claims Database Analysis of Differences in Antidepressant Treatment Persistence Associated With Escitalopram and Other Selective Serotonin Reuptake Inhibitors in the United States

Background: Although previous studies have found no differences in response to antidepressant pharmacotherapy between selective serotonin reuptake inhibitors (SSRIs), some recent trials suggest benefits associated with more rapid onset of action. Objective: The aim of this work was to compare the likelihood that patients initiating treatment with branded escitalopram, rather than with any of 3 SSRIs (le, citalopram, fluoxetine, and paroxetine) that are available in generic or branded formulations, would continue therapy with the initial medication after 2 and 6 months. Methods: We used propensity score-weighted logistic regression to assess the effect of antidepressant choice on the likelihood of continuing treatment, based on data from a large administrative claims database with information about US patients. We modeled the propensity to initiate treatment with escitalopram based on demographic, diagnostic, insurance, and service-use characteristics in the 6 months before treatment initiation and used the results to calculate weights for analysis of treatment continuation. The primary outcome measures were receipt of 2 prescriptions of the index drug in the first 2 months and, among those continuing at 2 months, 4 prescriptions in the first 6 months. Antidepressant choice, cost, and service-use characteristics during the treatment period were included as covariates. Patients who initiated therapy between July 2002 and April 2005 were eligible for inclusion. Results: Based on data for 43,921 patients, at 2 months, escitalopram initiators were more likely to have continued initial medication than those receiving the other SSRIs (66.1% vs 61.9%, respectively; P < 0.01) and less likely to have switched or augmented treatment (4.8% vs 7.6%; P < 0.01). At 6 months, escitalopram-treated patients were also more likely to have continued initial medication (47.1% vs 41.0%; P < 0.01) and less likely to have switched or augmented treatment (9.4% vs 14.4%; P < 0.01). Conclusion: Patients initiating treatment with escitalopram were more likely to continue and less likely to switch or augment treatment at 2 and 6 months of therapy compared with those who initiated with alternative SSRIs. (Clin Ther. 2009;31:644-656) (C) 2009 Excerpta Medica Inc.