Economic consequence of switching to citalopram after its generic entry for adult patients with major depressive disorder (MDD) treated with escitalopram: a 6-month retrospective study

Abstract Objective: To estimate, from a third-party payer's perspective, the effects of switching from escitalopram to citalopram, after the generic entry of citalopram, on hospitalization and healthcare costs among adult MDD patients who were on escitalopram therapy. Methods: Adult MDD patients treated with escitalopram were identified from Ingenix Impact claims database. MDD- and mental health (MH)-related hospitalization rates and healthcare costs were compared between 'switchers' (patients who switched to citalopram after its generic entry) and 'non-switchers'. MDD- and MH-related outcomes were defined as having a primary or a secondary diagnosis of ICD-9-CM = 296.2x, 296.3x and ICD-9-CM = 290-319, respectively. A propensity score matching method that estimated the likelihood of switching using baseline characteristics was used. Outcomes were examined for both 3-month and 6-month post-index periods. Results: The sample included 3,427 matched pairs with balanced baseline characteristics. Switchers were more likely to incur an MDD-related (odds ratio [OR] = 1.52) and MH-related hospitalization (OR = 1.34) during the 6-month post-index period (both p