A population-based examination of trends and disparities in medication treatment for opioid use disorders among Medicaid enrollees

Background: Medication treatment (MT) with methadone and buprenorphine are effective treatments for opioid use disorders, but little information is available regarding the extent to which buprenorphine's approval resulted in more individuals receiving MT nor to what extent receipt of such treatment was equitable across communities. Methods: To examine changes in MT utilization and the association between MT utilization and county-level indicators of poverty, race/ethnicity, and urbanicity, we used Medicaid claims of non-dually eligible Medicaid enrollees aged 18–64 from 14 states for 2002–2009. We generated county-level aggregate counts of MT (methadone, buprenorphine, and any MT) by year (N = 7760 county-years). We estimated count data models to identify associations between MT and county characteristics, including levels of poverty and racial/ethnic concentration. Results: The number of Medicaid enrollees receiving MT increased 62% from 2002 to 2009. The number of enrollees receiving methadone increased 20%, with the remaining increase resulting from buprenorphine. Urban county residents were significantly more likely to receive MT in both 2002 and 2009 than rural county residents. However, buprenorphine substantially increased MT in rural counties from 2002 to 2009. Receipt of MT increased at a much higher rate for residents of counties with lower poverty rates and lower concentrations of black and Hispanic individuals than for residents of counties without those characteristics. Conclusions: The increase in Medicaid enrollees receiving MT in the years following buprenorphine's approval is encouraging. However, it is concerning that MT trends varied so dramatically by characteristics of the county population and that increases in utilization were substantially lower in counties with populations that historically have been disadvantaged with respect to health care access and quality. Concerted efforts are needed to ensure that MT benefits are equitably distributed across society and reach disadvantaged individuals who may be at higher risk of experiencing opioid use disorders.