Substance Use
Racial Disparities in Buprenorphine Initiation and Retention Following Medicaid Expansion Anna T Nguyen* Anna Nguyen Nguyen Nguyen Stanford University, Department of Epidemiology and Population Health
Introduction: Buprenorphine is an effective treatment for opioid use disorder but is particularly underutilized among non-White populations. Medicaid Expansion under the Affordable Care Act increased buprenorphine access, but it is unclear how expansion impacted treatment disparities. Here, we use quasi-experimental methods to assess heterogeneity in the effect of Medicaid expansion on buprenorphine use by area-level racial composition.
Methods: We identified 154 million buprenorphine prescriptions across 4.7 million patients between Jan 2010 and Dec 2023 in the IQVIA longitudinal prescriptions database. We used generalized synthetic control models to estimate the effect of Medicaid Expansion on buprenorphine initiation (new prescription after ≥180 days of no treatment) and retention (continuous treatment for ≥180 days). We compared effect estimates between areas (ZIP3s) with small vs large Non-Hispanic White populations, based on quartiles estimated from 2010 Census data. We incorporated area-level educational attainment, household income, and poverty levels into the synthetic controls, and weighted effect estimates by population size.
Results: Following Medicaid Expansion, we found an overall increase of 5.7 (95% CI 2.1, 9.3) buprenorphine initiations per 100,000 people. This increase was driven by areas with the largest Non-Hispanic White populations, where initiations increased by 13.6 (95% CI 4.8, 22.3) per 100,000 people. There was no increase in areas with the smallest Non-Hispanic White populations (+0.3 per 100,000, 95% CI -4.7, 5.3). Buprenorphine retention declined starting five years after expansion, but we found no differences in this trend by area-level racial composition.
Conclusion: Medicaid Expansion only increased buprenorphine initiation in areas with large Non-Hispanic White populations. Additional efforts are needed to improve retention across all new users and address structural barriers that limit medication access in non-White populations.
