This technical appendix describes our approach to estimating the share of Medicaid enrollees ages 12 and older whose prescriptions for medication to treat opioid use disorder and overdose (MOUD) would have been paid by a managed-care organization in 2015 through 2018. We derive these enrollment shares using enrollment records from the Medicaid Statistical Information System (MSIS) and the Medicaid Analytic eXtract (MAX) and data reported in the Medicaid Budget and Expenditure System. We use state- and year-specific methods to account for changes in managed-care enrollment policy and varying MSIS/MAX data availability.
These estimates are used in an accompanying brief assessing the number of Medicaid prescriptions to treat opioid use disorder per 1,000 enrollees under fee-for-service and managed-care payment arrangements, as reported in Medicaid State Drug Utilization Data.