State-level influences on buprenorphine utilization: Variations in opioid addiction treatment

Background: Buprenorphine, used to treat opioid addiction, requires physicians to have special Drug Enforcement Agency certification to prescribe. There are wide geographic variations in buprenorphine use. The purpose of this study was to identify state-level influences on buprenorphine prescribing using a limited set of supply and demand measures. Methods: We developed a database using data on buprenorphine prescribing and factors hypothesized to influence variations in prescribing, with data from 2005-2008. Factors included prevalence of past-year use of opioids, number of certified buprenorphine prescribers, number of opioid treatment programs (OTPs), state spending on substance abuse treatment and prevention, and Medicaid coverage of buprenorphine. Linear regression models were constructed with the log of the cumulative grams of buprenorphine distributed in each state in 2008 per 1000 users as the dependent variable. Results: From 2005 to 2009, buprenorphine use increased from 13g to 97g/year/1000 users. Buprenorphine use was highest in the Northeast. The supply of certified physicians per 10,000 users was highest in Vermont, Maine, and the District of Columbia. In multivariate analyses, only the supply of physicians remained significantly associated with higher buprenorphine volume. Discussion: Buprenorphine use has increased rapidly over the past 5 years. Physician supply was significantly associated with greater buprenorphine use, whereas the level of state spending on substance abuse treatment and Medicaid coverage did not appear to predict buprenorphine volume.