title: Illicit use of opioid substitution drugs: prevalence, user characteristics, and the association with non-fatal overdoses.
abstract: OBJECTIVE
  Diversion of opioid substitution drugs (OSD) is of public concern. This study examined the prevalence, frequency, and predictors of illicit OSD use in a group of injecting drug users (IDUs) and assessed if such use was associated with non-fatal overdoses.
  
  
  METHODS
  Semi-annual cross-sectional interviews conducted in Oslo, Norway (2006-2013), from 1355 street-recruited IDUs. Hurdle, logistic, and multinomial regression models were employed.
  
  
  RESULTS
  Overall, 27% reported illicit OSD use in the past four weeks; 16.8% methadone, 12.5% buprenorphine, and 2.9% both drugs. Almost 1/10 reported at least one non-fatal overdose in the past four weeks, and roughly 1/3 reported such experience in the past year. Use of additional drugs tended to be equally, or more prevalent among illicit OSD users than other IDUs. In terms of illicit OSD use being a risk factor for non-lethal overdoses, our results showed significant associations only for infrequent buprenorphine use (using once or less than once per week). Other factors associated with non-fatal overdoses included age, education, homelessness, as well as the benzodiazepines, stimulants, and heroin use.
  
  
  CONCLUSIONS
  Users of diverted OSD may represent a high-risk population, as they used more additional drugs and used them more frequently than other IDUs. However, illicit OSD use may be less harmful than previously assumed. After accounting for an extensive set of covariates, only infrequent illicit buprenorphine use, but not methadone use, was associated with non-fatal overdoses.
authors.affiliation: Norwegian Institute for Alcohol and Drug Research (SIRUS), PB 565 Sentrum, 0105 Oslo, Norway. Electronic address: alb@sirus.no.
authors.forename: Anne Line
authors.initials: AL
authors.lastname: Bretteville-Jensen
authors.affiliation: Norwegian Institute for Alcohol and Drug Research (SIRUS), PB 565 Sentrum, 0105 Oslo, Norway.
authors.forename: Mats
authors.initials: M
authors.lastname: Lillehagen
authors.affiliation: Norwegian Institute for Alcohol and Drug Research (SIRUS), PB 565 Sentrum, 0105 Oslo, Norway.
authors.forename: Linn
authors.initials: L
authors.lastname: Gjersing
authors.affiliation: Norwegian Institute for Alcohol and Drug Research (SIRUS), PB 565 Sentrum, 0105 Oslo, Norway.
authors.forename: Jasmina Burdzovic
authors.initials: JB
authors.lastname: Andreas
mesh_terms: D000328:Adult; D002047:Buprenorphine / Q000009:adverse effects*; D003430:Cross-Sectional Studies; D062787:Drug Overdose / Q000175:diagnosis* / Q000453:epidemiology; D055030:Drug Users; D005260:Female; D003932:Heroin / Q000009:adverse effects; D006801:Humans; D013287:Illicit Drugs / Q000009:adverse effects*; D008297:Male; D008691:Methadone / Q000009:adverse effects*; D008875:Middle Aged; D009664:Norway / Q000453:epidemiology; D058850:Opiate Substitution Treatment / Q000009:adverse effects / Q000379:methods; D009293:Opioid-Related Disorders / Q000175:diagnosis* / Q000453:epidemiology; D015995:Prevalence; D012307:Risk Factors; D055815:Young Adult
chemical_list: D013287:Illicit Drugs; D002047:Buprenorphine; D003932:Heroin; D008691:Methadone
keywords: Buprenorphine; Diversion; Injecting drug users; Methadone; Opioid substitution treatment