The Medicaid Expansion and the Uptake of Medication-assisted Treatment for Opioid Use Disorder: Evidence from the Rhode Island All-payer Claims Database, 2012–2018 The Medicaid Expansion and the Uptake of Medication-assisted Treatment for Opioid Use Disorder: Evidence from the Rhode Island All-payer Claims Database, 2012–2018

This article uses the all-payer claims database for the state of Rhode Island to assess recent progress in the state toward the goal of expanding access to medication-assisted treatment (MAT) for opioid use disorder (OUD). The analysis highlights the role played by the Affordable Care Act (ACA) and the associated Medicaid expansion in furthering that goal. Using measures that account for changes in health insurance enrollment, we find that the MAT rate per 100,000 enrollees in Rhode Island effectively doubled between 2012 and 2018, while the prevalence of OUD in the sample also doubled over the same period. Taken at face value, it would appear that the growth in the MAT rate over the period was just sufficient to meet the increased need for treatment. However, when we analyze the trends in MAT rates and OUD rates separately for Medicaid enrollees and non-Medicaid enrollees, the progress in treating OUD patients with MAT seems to have been much greater for the Medicaid population. In terms of raw numbers, the largest single-year gain in the number of patients receiving MAT occurred in 2014, the year when the ACA and Medicaid expansion went into effect. Among the first-time enrollees of 2014 who received MAT, over 80 percent were Medicaid enrollees, and those individuals accounted for more than one-third of the overall increase in MAT patients from the previous year. The analysis also suggests that expanded uptake of MAT may have contributed to the decline in opioid-related mortality in Rhode Island that occurred between 2016 and 2018, although more recent (preliminary) evidence suggests that Rhode Island as well as the rest of the country saw a resurgence in opioid-related mortality in 2020.