Access to Health Insurance and Treatment Utilization for Opioid Use Disorder: Evidence From State Medicaid Expansions
Abstract Background. Medicaid is a major payer of substance use disorder treatment, yet the impact of Medicaid expansion on the opioid epidemic has not been sufficiently quantified. This study exploits state-level differences in Medicaid expansion to assess the impact of access to health insurance on treatment utilization for opioid use disorder (OUD) for adults in need.Method. We use admissions data from Treatment Episode Data Sets (TEDS) to fit a multivariate difference-in-difference model, with non-expanding states as controls, adjusting for age, gender, race/ethnicity, education, and other state-level factors. Results. Medicaid expansion led to substantial gain in OUD treatment utilization. Admissions for substance use disorder among Medicaid beneficiaries increased by 20-33 percentage points in expansion states. Admissions were significantly higher for the newly eligible Medicaid beneficiaries in the 30-34 age group. We also see an increase in treatment admissions for opioid and heroin use among the elderly over the age of 55. Uninsurance rates show a commensurate decline in the expansion states. Finally, we do not find strong evidence of crowding-out of private insurance. Conclusions. Overall, our findings suggest that Medicaid expansions had a positive impact on the financing and utilization of opioid use treatment.