Objectives: To assess the impact of the expansion of Medicaid eligibility in the United States on the opioid epidemic, as measured through increased access to opioid analgesic medications and medication-assisted treatment.
Methods: Using Medicaid enrollment and reimbursement data from 2011 to 2016 in all states, we evaluated prescribing patterns of opioids and the 3 Food and Drug Administration-approved medications used in treating opioid use disorders by using 2 statistical models. We used difference-in-differences and interrupted time series models to measure prescribing rates before and after state expansions.
Results: Although opioid prescribing per Medicaid enrollee increased overall, we observed no statistical difference between expansion and nonexpansion states. By contrast, per-enrollee rates of buprenorphine and naltrexone prescribing increased more than 200% after states expanded eligibility, while increasing by less than 50% in states that did not expand. Methadone prescribing decreased in all states in this period, with larger decreases in expansion states.
Conclusions: The Medicaid expansion enrolled a population no more likely to be prescribed opioids than the base Medicaid population while significantly increasing uptake of 2 drugs used in medication-assisted treatment.