States' implementation of the Affordable Care Act and the supply of physicians waivered to prescribe buprenorphine for opioid dependence

Background: Although the Affordable Care Act (ACA) is anticipated to affect substance use disorder (SUD) treatment, its impact on the supply of physicians waivered to treat opioid dependence with buprenorphine has not been considered. This study examined whether states more supportive of ACA, meaning those that had opted to expand Medicaid and establish a state-based health insurance exchange, experienced greater growth in physician supply than less supportive states. Methods: Buprenorphine physician supply, including total physician supply, supply of 30-patient physicians, and supply of 100-patient physicians per 100,000 state residents, was measured from June 2013 to May 2015. State characteristics were drawn from multiple secondary sources, with states categorized as ACA-supportive, ACA-hybrid (where states either expanded Medicaid or established a state-based exchange), or ACA-resistant (where states took neither action). Mixed effects regression was used to estimate state-level growth curves to test whether rates of growth varied by states' approaches to implementing ACA. Results: The supply of waivered physicians grew significantly over the two-year period. Rates of growth were significantly lower in ACA-hybrid and ACA-resistant states relative to growth in ACA-supportive states. Average buprenorphine physician supply at baseline varied by region, the percentage of residents covered by Medicaid, and the supply of specialty SUD treatment programs. Conclusions: This study found a positive impact of the ACA on growth in the supply of buprenorphine-waivered physicians in US states. Future research should address whether the ACA affects the number of patients receiving buprenorphine, Medicaid spending, and the quality of treatment services delivered. (C) 2015 Elsevier Ireland Ltd. All rights reserved.