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 (ie, 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, escitalopramtreated 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.