Buprenorphine Initiation and Linkage to Outpatient Buprenorphine do not Reduce Frequency of Injection Opiate Use Following Hospitalization

Abstract

Background: Buprenorphine has established effectiveness for outpatient treatment of opioid use disorder. Our previously published STOP (Suboxone Transition to Opiate Program) trial showed that buprenorphine induction, stabilization, and linkage to outpatient treatment in opioid-dependent inpatients (injection and non-injection drug users) decreased illicit opioid use over 6months. The present study was a planned subgroup analysis of injection opiate users from STOP.

Objective: To determine if inpatient buprenorphine initiation and linkage to outpatient buprenorphine reduce injection opiate users' frequency of injection opiate use (IOU).

Methods: Inpatient injection opiate users at a safety-net hospital were randomized to buprenorphine linkage (induction, stabilization, bridge prescription, and facilitated referral to outpatient treatment) or detoxification (5-day inpatient buprenorphine taper). Conditional fixed-effects Poisson regression was used to estimate the effects of intervention on 30-day (self-report) at 1, 3, and 6months, measured using 30-day timeline follow-back. The secondary outcome was linkage effectiveness, measured as % presenting to initial outpatient buprenorphine visits after hospital discharge.

Results: Analysis was limited to persons (n=62 randomized to detoxification and n=51 to linkage) with baseline IOU. There were no significant differences in age, ethnicity, or baseline IOU frequency. At follow-up, linkage patients (70.6%) were significantly more likely (p<0.001) to present to initial buprenorphine visits than detoxification patients (9.7%). However, there was no significant between group difference in the rate of IOU at 1- (IRR=0.73, p=0.32), 3- (IRR=1.20, p=0.54), or 6-month (IRR=0.73, p=0.23) follow-ups. Using person-day analysis, participants self-reported IOU on 5.8% of follow-up days in which they used prescription buprenorphine and 37.5% of non-buprenorphine days. Using a generalized estimating equation, the estimated odds of IOU was 4.57 times higher (p<0.001) on non-buprenorphine days.

Conclusions: Despite STOP's success in linking patients who inject opiates to outpatient buprenorphine, the intervention did not significantly decrease their IOU frequency. Injection opiate users will require a more intensive protocol to sustain outpatient buprenorphine treatment and decrease injection with its attendant risks.

Keywords: Buprenorphine; Hospitalization; Injection drug use; Opioid use disorder; Transitions of care.