OBJECTIVES : Many patients with major depressive disorder (MDD) switch or prematurely discontinue antidepressant therapy. This study aims to describe patient characteristics, healthcare resource utilization, and antidepressant persistence for patients continuing (≤45-day gap in refills following index fill), discontinuing, or switching therapies.

METHODS : This retrospective cohort study used US claims data from the HealthCore Integrated Research Database between 01/2014–02/2019 (index date=earliest antidepressant fill between 01/2015–02/2019). Patients were aged 18–64 years with ≥2 MDD diagnoses (including a diagnosis between 12 months prior and 1 month after index date) and continuous enrollment for 12 months before and after the index date. Pre-index and 1-year post-index patient characteristics and healthcare resource utilization are presented using descriptive statistics.

RESULTS : Of 134,237 patients meeting study criteria, 39,121 (29.1%) were continuing, 34,457 (25.7%) switching, and 60,659 (45.2%) discontinuing therapies. Selective serotonin reuptake inhibitors were the most commonly prescribed (62%–68%) index antidepressant, followed by bupropion and mirtazapine (12%–15%). Mean age was 39.2, 42.9, and 40.0 years for patients switching, continuing, and discontinuing, respectively. The pre-index prevalence of co-morbid anxiety (using predefined ICD-9-CM and ICD-10-CM codes) was higher with switching than continuing/discontinuing (37% vs 30%–31%) and increased after post-index (66% vs 48%–52%). Pre-index office visits were highest among patients switching, which increased further post-index. Patients continuing and discontinuing had stable or reduced MDD-related inpatient/emergency room utilization post-index, while switchers showed an increase (inpatient, 5.6%–7.7%; emergency room, 3.9%–6.0%). Mean pre-index overall healthcare costs (medical+pharmacy) were higher with switching ($14,842) vs continuing ($13,474) and discontinuing ($12,612), and further increased with switching post-index ($17,731) vs continuing ($14,181) and discontinuing ($12,534).

CONCLUSIONS : Patients who switch antidepressant therapy are younger, with comorbid anxiety disorders. Switching therapies is associated with higher overall healthcare costs and utilization. Future analyses will assess reasons for switching and/or discontinuation.