Associations between stimulant use and return to illicit opioid use following initiation onto medication for opioid use disorder.
This study was a secondary analysis of two CTN trials comparing buprenorphine (BUP-NX) and extended-release naltrexone (XR-NTX), CTN-0051, X:BOT and CTN-0067, CHOICES. The purpose was to estimate how ongoing stimulant use affects return to illicit opioid use after initiation onto medication for opioid use disorder (MOUD).
A total of 528 participants who initiated MOUD as part of trial participation were included; participants were recruited from 13 opioid treatment programs and HIV clinics across 10 states in the U.S. from 2014-2019. Nearly half (49%) were between 30 and 49 years of age, 69% were male and 66% were non-Hispanic White.
The primary outcome was first self-reported day of non-prescribed opioid use following MOUD initiation, and the exposure of interest was daily stimulant use (methamphetamine, amphetamines or cocaine). Both were defined using time-line follow-back. Among participants reporting at least 1 day of illicit opioid use, we also examined relapse to ongoing use, defined as (1) 7 days of continuous opioid use or (2) 4 consecutive weeks with self-reported opioid use, one or more positive urine drug screens (UDS) for opioids or one or more missing UDS.
Forty-seven per cent of participants reported stimulant use following MOUD initiation, 58% returned to illicit opioid use and 66% of those relapsed to ongoing use. Stimulant use was strongly associated with increased risk of misusing opioids after MOUD initiation when measured daily [adjusted hazard ratio (aHR)=9.23, 95% confidence interval (CI)=6.80–12.50, P<0.001] and over a 7-day period (aHR=1.27 for each additional day, CI=1.18–1.37, P<0.001). Using stimulants weekly or more often was associated with increased likelihood of relapse to ongoing opioid use compared with less than weekly or no stimulant use (adjusted odds ratio=2.30, CI=1.05–5.39, P=0.044).
Conclusions: People initiated on medication for opioid use disorder who subsequently use stimulants appear to be more likely to return to and continue using non-prescribed opioids compared with those without stimulant use. The association appears to be stronger among patients who initiate buprenorphine compared with those who initiate extended-release naltrexone.
Related protocols: CTN-0051, CTN-0067