Utilization of buprenorphine and methadone among opioid users who inject drugs

Background: There has been a rise in opioid abuse and related injection drug use in the United States, and treatment for opioid use disorders may be underutilized. The study aim was to describe utilization of opioid agonist therapy (OAT), and assess factors associated with utilization of OAT, among persons who inject drugs (PWID) in the Seattle metropolitan area.

Methods: Data were obtained from the 2015 National HIV Behavioral Surveillance (NHBS) system among PWID in the Seattle area. Persons aged ≥18 years who injected drugs in the past year were recruited using respondent-driven sampling. Local supplemental questions assessed whether participants had received methadone or buprenorphine treatment in the past year. The analysis was restricted to participants who reported use of any opioids in the past year. Analyses compared the demographic, health insurance status, duration of injection drug use, prior history of overdose, prior receipt of hepatitis C virus/human immunodeficiency virus (HCV/HIV) testing (self-report), and screening positive for HCV/HIV via study testing between methadone- or buprenorphine-treated and untreated PWID. Multivariate logistic models were performed to assess adjusted associations with receipt of any OAT.

Results: The sample included 487 PWID who used opioids in the past year, of whom 27.1% (95% confidence interval [CI]: 23.1-31.1) reported past-year treatment with methadone and 4.7% (95% CI: 2.8-6.6) reported treatment with buprenorphine. There were no significant differences in demographics among participants who did and did not report past-year OAT; however, participants who were treated with methadone were more likely to be insured and have hepatitis C. After adjustment for other covariates, having health insurance was strongly associated with receipt of OAT (adjusted odds ratio [aOR] = 18.6; 95% CI: 2.5-138.7).

Conclusions: OAT, in particular buprenorphine, has been underutilized by opioid-using PWID in the Seattle area. Health insurance is a critical factor for enabling PWID to utilize OAT treatment for opioid use disorders.