Impact of Atypical Antipsychotics as Adjunctive Therapy on Psychiatric Cost and Utilization in Patients with Major Depressive Disorder

Patients with major depressive disorder (MDD) incur high costs, despite established treatment options. Adding an atypical antipsychotic (AAP) to antidepressant therapy has shown to reduce depressive symptoms in MDD, but it remains unclear with which adjunctive AAP to initiate. As economic burden is one factor that can influence treatment selection, this study's objective was to evaluate the impact of adjunctive AAP choice on psychiatric costs and healthcare utilization in MDD.

This retrospective cohort study analyzed de-identified data from: (1) IBM^® MarketScan^® Commercial (C), Medicare Supplemental (MS), and MarketScan Multi-State Medicaid (M) Databases, and (2) Optum^® Clinformatics^® Datamart. Adult MDD patients were included if they had: initiated adjunctive AAPs during study identification period (7/1/15-9/30/16 MarketScan C/MS, and Optum; 7/1/15-6/30/16 MarketScan M), and ≥12 months of continuous enrollment before (baseline) and after (follow-up) first treatment date. Models included generalized linear models (GLMs) for psychiatric costs (total inpatient and outpatient services, excluding outpatient pharmacy costs), and a two-part model (logistic regression for psychiatric hospitalizations, GLM for psychiatric hospitalization costs among hospitalized patients); models were adjusted for baseline characteristics.

The final study sample consisted of 10,325 patients (7657 aripiprazole, 1219 brexpiprazole, 827 lurasidone, 622 quetiapine). Using brexpiprazole as reference, lurasidone and quetiapine users had $1662 and $3894 higher psychiatric costs, respectively. Psychiatric costs were not statistically significantly different between aripiprazole and brexpiprazole (p>0.05). Quetiapine users had $15,159 (p<0.001) higher psychiatric hospitalization costs among those hospitalized, and higher odds of psychiatric hospitalization [2.11 (1.46-3.04); p<0.001] compared to brexpiprazole users. No statistically significant differences observed in psychiatric hospitalization risk comparing aripiprazole and lurasidone with brexpiprazole (p>0.05).

In MDD, brexpiprazole users had significantly lower psychiatric costs than lurasidone and quetiapine users, and significantly lower psychiatric hospitalization risk than quetiapine users. Adjunctive AAP choice may impact subsequent healthcare costs and utilization in MDD.