(160) Trajectories of Pharmacological Therapies for Treatment-Resistant Depression: A Large Longitudinal Study based on Commercial Claims Data Linked to Electronic Medical Records

Publication Number: 495

Background: Treatment-resistant depression (TRD) is commonly defined in patients with major depressive disorder (MDD) as unremitting depression following ≥2 antidepressant regimens at adequate dose and duration. Few studies have examined the natural history of TRD including treatment trajectories (choice of treatment course across different lines of therapies) of TRD patients.

Objectives: To describe patient characteristics and treatment trajectories for TRD patients.

Methods: A retrospective longitudinal study was conducted using the IBM MarketScan Explorys Claims-EMR Data from January 1, 2017 to October 31, 2021. TRD patients were identified as receiving third-line antidepressant treatment ≤2 years after initiating first-line antidepressants (index date). Participants were required to be ≥18 years, have ≥1 MDD diagnosis, have no use of antidepressants in the baseline period (one year before the index date), and have continuous enrollment during the baseline and identification periods. Participants were excluded if they had other psychiatric or other mood disorders. Descriptive analysis characterized TRD treatment trajectories. Sensitivity analyses included patients with other mood disorders.

Results: Seven percent (n=5,182) of MDD patients receiving antidepressants met criteria for TRD after applying all inclusion/exclusion criteria except the presence of other mood disorders; the TRD population decreased to 4,101 (4.8%) after excluding patients with other mood disorders. Most TRD patients were aged between 18-34 (44.2%) and female (71.0%) and the most common comorbidity was anxiety (46.3%). SSRI monotherapy was used most frequently as first (58.8%) and second-line therapy (29.4%); the most common treatment trajectory (26.7%) was the use of different types of SSRIs and SSRIs combined with other antidepressants or augmentation medications as the first-, second-, and third-line treatments. The most common augmentation therapy in first- and second-line treatment was anxiolytics (first-line: 4.6%; second-line: 15.0%), and in third-line treatment, was antipsychotics (23.2%). The mean time (±SD) from first to second therapy, second to third therapy, and to TRD was 186.2 days (±144.8), 194.1 days (±145.0), and 380.3 days (±181.3), respectively. The mean duration (±SD) of TRD episode (days between first and last recorded MDD diagnosis) was 761.2 days (±469.8). Sensitivity analyses including patients with mood disorders were consistent with the main analysis.

Conclusions: SSRIs were the most common class of medications in first and second line therapy in TRD patients. The relatively long mean duration of TRD episode highights the substantial health related burden associated with this condition.