An episode level evaluation of the treatment journey of patients with major depressive disorder and treatment-resistant depression

Abstract

Background Many patients with major depressive disorder (MDD) fail to respond to antidepressant (AD) pharmacotherapy. The objectives of this study were to characterize MDD and treatment-resistant depression (TRD) at the level of pharmacologically treated episodes and to describe the sequential treatment patterns by lines of therapy (LOT) in the first two episodes. Methods Adults (18 years of age) with continuous enrollment 12 months before and after the first MDD diagnosis and treated with an AD, with or without an MDD-indicated antipsychotic (AP), were identified (1/1/2010-12/31/2015). The MDD episode started on the date of MDD diagnosis that was preceded by a clean period without any MDD diagnosis. The MDD episode ended on the last MDD diagnosis or the end of the days’ supply of AD/AP medication, whichever came last. TRD was defined as an MDD episode with 3 AD/AP regimens. Measured outcomes included episode duration, number of LOT, relapse hospitalization, and sequential treatment patterns of MDD episode stratified by TRD and non-TRD episodes. Results Of 48,440 patients who received AD/AP in the 1st MDD episode, 3,317 (6.8%) of episodes were considered TRD. Mean duration of 1st TRD episodes was 571 days, mean number of AD/AP LOTs was 3.47, and 13.7% involved relapse hospitalization. Mean duration of 1st non-TRD episodes was 200 days, mean number of AD/AP LOTs was 1.21, and 9.6% involved relapse hospitalization. Among 1st MDD episodes, 25.5% had a second LOT; 7.3% had a third LOT. Most patients received selective serotonin reuptake inhibitors (SSRIs) as the first LOT (63.0%), and the plurality of regimens were SSRIs in second (44.9%) and third LOT (41.1%). Conclusions Compared to non-TRD episodes, TRD episodes were longer and more often involved relapse hospitalizations. SSRIs were the most common treatment; treatment changes and potential treatment unresponsiveness were frequent among MDD patients.