The effect of Medicaid expansion on state-level utilization of buprenorphine for opioid use disorder in the United States.

BACKGROUND

Research on the impact of Medicaid expansion on buprenorphine utilization has largely focused on the Medicaid program. Less is known about its associations with total buprenorphine utilization and non-Medicaid payers.

METHODS

Monthly prescription data (June 2013-May 2018) for proprietary and generic sublingual as well as buccal buprenorphine products were purchased from IQVIA®. Population-adjusted state-level utilization measures were constructed for Medicaid, commercial insurance, Medicare, cash, and total utilization. A difference-in-differences (DID) approach with population weights estimated the association between Medicaid expansion and buprenorphine utilization, while controlling for treatment capacity.

RESULTS

Monthly total buprenorphine prescriptions increased by 68% overall and increased 283% for Medicaid, 30% for commercial insurance, and 143% for Medicare. Cash prescriptions decreased by 10%. The DID estimate for Medicaid expansion was not statistically significant for total utilization (-19.780, 95% CI = -45.118, 5.558, p = .123). For Medicaid buprenorphine utilization, there was a significant increase of 27.120 prescriptions per 100,000 total state residents (95% CI = 9.458, 44.782, p = .003) in expansion states versus non-expansion states post-Medicaid expansion. Medicaid expansion had a negative effect on commercial insurance (DID estimate = -37.745, 95% CI = -62.946, -12.544, p = .004), cash utilization (DID estimate = -6.675, 95% CI = -12.627, -0.723, p = .029), and Medicare utilization (DID estimate = -1.855, 95% CI = -3.697, -0.013, p = .048).

DISCUSSION

The associations between Medicaid expansion and buprenorphine utilization varied across different types of payers, such that the overall impact of Medicaid expansion on buprenorphine utilization was not significant.