title: Predictors of non-use of illicit heroin in opioid injection maintenance treatment of long-term heroin dependence.
abstract: OBJECTIVE
  To investigate baseline and concurrent predictors of non-use of illicit heroin among participants randomized to injectable opioids in the North American Opiate Medication Initiative (NAOMI) clinical trial.
  
  
  METHODS
  NAOMI was an open-label randomized controlled trial comparing the effectiveness of injectable diacetylmorphine and hydromorphone for long-term opioid-dependency. Outcomes were assessed at baseline and during treatment (3, 6, 9, 12months). Days of non-use of illicit heroin in the prior month at each follow-up visit were divided into three categories: Non-use; Low use (1 to 7days) and High use (8days or more). Tested covariates were: Sociodemographics, Health, Treatment, Drug use and illegal activities. Mixed-effect proportional odds models with random intercept for longitudinal ordinal outcomes were used to assess the predictors of the non-use of illicit heroin.
  
  
  RESULTS
  139 participants were included in the present analysis. At each follow-up visit, those with non-use of illicit heroin represented 47.5% to 54.0% of the sample. Fewer days of cocaine use (p=0.074), fewer days engaged in illegal activities at baseline (p<0.01) and at each visit (p<0.01), less money spent on drugs (p<0.001), days with injection opioid or oral methadone treatment (p<0.001) and total mg of injectable opioids taken (p<0.001), independently predicted lower use of illicit heroin.
  
  
  CONCLUSIONS
  The independent effect of several concurrent factors besides the injection of opioid dose suggests benefits from the clinic that go beyond the provision of the medication alone. Thus, this supervised model of care presents an opportunity to maximize the beneficial impact of medical and psychosocial components of the treatment on improving outcomes associated with non-use of illicit heroin.
authors.affiliation: Centre for Health Evaluation & Outcome Sciences, Providence Health Care, St. Paul's Hospital, 575-1081 Burrard St., Vancouver, BC V6Z 1Y6, Canada; School of Population and Public Health, University of British Columbia, 2206 East Mall, Vancouver, BC, V6T 1Z3, Canada. Electronic address: eugenia@cheos.ubc.ca.
authors.forename: Eugenia
authors.initials: E
authors.lastname: Oviedo-Joekes
authors.affiliation: Centro Nacional de Epidemiología, Instituto de Salud Carlos III, Madrid, Spain; Departamento de Medicina Preventiva y Salud Pública, Universidad Complutense de Madrid, Spain; Ciber en Epidemiología y Salud Pública, CIBERESP, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Sordo
authors.affiliation: Centre for Health Evaluation & Outcome Sciences, Providence Health Care, St. Paul's Hospital, 575-1081 Burrard St., Vancouver, BC V6Z 1Y6, Canada.
authors.forename: Daphne
authors.initials: D
authors.lastname: Guh
authors.affiliation: Centre for Addiction Research BC, University of Victoria, 2300 McKenzie Ave, Victoria, BC V8P 5C2, Canada; Northern Ontario School of Medicine, 955 Oliver Road, Thunder Bay, ON P7B 5E1, Canada.
authors.forename: David C
authors.initials: DC
authors.lastname: Marsh
authors.affiliation: Centre for Health Evaluation & Outcome Sciences, Providence Health Care, St. Paul's Hospital, 575-1081 Burrard St., Vancouver, BC V6Z 1Y6, Canada.
authors.forename: Kurt
authors.initials: K
authors.lastname: Lock
authors.affiliation: Centre Hospitalier de l'Université de Montréal, Hôpital Saint-Luc, CHUM Montréal, QC H2X 3J4, Canada.
authors.forename: Suzanne
authors.initials: S
authors.lastname: Brissette
authors.affiliation: Centre for Health Evaluation & Outcome Sciences, Providence Health Care, St. Paul's Hospital, 575-1081 Burrard St., Vancouver, BC V6Z 1Y6, Canada; School of Population and Public Health, University of British Columbia, 2206 East Mall, Vancouver, BC, V6T 1Z3, Canada.
authors.forename: Aslam H
authors.initials: AH
authors.lastname: Anis
authors.affiliation: Centre for Health Evaluation & Outcome Sciences, Providence Health Care, St. Paul's Hospital, 575-1081 Burrard St., Vancouver, BC V6Z 1Y6, Canada; School of Population and Public Health, University of British Columbia, 2206 East Mall, Vancouver, BC, V6T 1Z3, Canada.
authors.forename: Martin T
authors.initials: MT
authors.lastname: Schechter
mesh_terms: D000328:Adult; D005260:Female; D005500:Follow-Up Studies; D003932:Heroin / Q000008:administration & dosage / Q000627:therapeutic use*; D006556:Heroin Dependence / Q000188:drug therapy*; D006801:Humans; D004091:Hydromorphone / Q000008:administration & dosage / Q000627:therapeutic use*; D007267:Injections; D008297:Male; D009294:Narcotics / Q000008:administration & dosage / Q000627:therapeutic use*; D013995:Time; D016896:Treatment Outcome
chemical_list: D009294:Narcotics; D003932:Heroin; D004091:Hydromorphone
keywords: Diacetylmorphine; Heroin dependence; Hydromorphone; Injectable opioids maintenance