Impact of social determinants of health on esketamine nasal spray initiation among patients with treatment-resistant depression in the United States.

Background: Disparities in mental health care access and health outcomes based on sociodemographic factors in the United States have been extensively documented. However, there is limited knowledge regarding these socioeconomic factors with respect to initiation of esketamine nasal spray, a novel therapy for treatment-resistant depression (TRD).

Objective: To evaluate the association of socioeconomic factors with the initiation of esketamine nasal spray.

Methods: Adults with TRD and commercial or Medicare Advantage (MA) insurance (Commercial-MA cohort) were included from Optum's deidentified Clinformatics Data Mart Database (January 2016-June 2022) and adults with Medicaid insurance (Medicaid cohort) were included from Merative MarketScan Multi-State Medicaid Database (January 2016-June 2022). The baseline period spanned 12 months before the index date (latter of evidence of TRD or US esketamine approval date); follow-up period spanned the index date until the end of health plan eligibility/data availability. Multivariate Cox proportional hazard models were used, separately for each cohort, to evaluate the association of characteristics with time to esketamine initiation; patients who did not initiate esketamine were censored at the end of follow-up.

Results: In the Commercial-MA cohort, 201,937 patients were included (75.0% female, mean age 62.3 years, 80.9% White, 82.8% having less than a bachelor's degree, 60.3% with a household income less than $75,000). Having both an education of less than a bachelor's degree and a household income less than $75,000 reduced the chance of esketamine initiation by 37% (hazard ratio [HR] = 0.63, P < 0.001). In the Medicaid cohort, 51,206 patients were included (77.8% female, mean age 43.2 years, 78.6% White). In both cohorts, chances of initiation trended to be lower in females (Commercial-MA: HR = 0.63, P < 0.001; Medicaid: HR = 0.68, P = 0.088), whereas racial or ethnic minorities had similar chances of initiation to White patients (Commercial-MA: HR = 1.23, P = 0.104; Medicaid: HR = 0.79, P = 0.376).

Conclusions: Disparities in esketamine nasal spray initiation were observed based on education, income, and gender highlighting a potential health equity gap.