title: The impact of low-threshold methadone maintenance treatment on mortality in a Canadian setting.
abstract: BACKGROUND
  Methadone maintenance therapy (MMT) is among the most effective treatment modalities available for the management of opioid use disorder. However, the effect of MMT on mortality, and optimal strategies for delivering methadone are less clear. This study sought to estimate the effect of low-threshold MMT and its association with all-cause mortality among persons who inject drugs (PWID) in a setting where methadone is widely available through primary care physicians and community pharmacies at no cost through the setting's universal medical insurance plan.
  
  
  METHODS
  Between May, 1996 and December, 2011 data were collected as part of two prospective cohort studies of PWID in Vancouver, Canada, and were linked to the provincial vital statistics database to ascertain rates and causes of death. The association of MMT with all-cause mortality was estimated using multivariable extended Cox regression with time-dependent variables.
  
  
  RESULTS
  Of 2335 PWID providing 15027 person-years of observation, 511 deaths were observed for a mortality rate of 3.4 (95% Confidence Interval [CI]: 3.1-3.7) deaths per 100 person-years. After adjusting for potential confounders including age and HIV seropositivity, MMT enrolment was found to be associated with lower mortality (adjusted hazard ratio [AHR]=0.73, 95% CI: 0.61-0.88).
  
  
  CONCLUSIONS
  While observed all-cause mortality rates among PWID in this setting were high, participation in low-threshold MMT was significantly associated with improved survival. These findings add to the known benefits of providing low-threshold MMT on reducing the harms associated with injection drug use.
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6; Department of Medicine, University of British Columbia, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6. Electronic address: seonaidn@gmail.com.
authors.forename: Seonaid
authors.initials: S
authors.lastname: Nolan
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6; Department of Medicine, University of British Columbia, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6.
authors.forename: Kanna
authors.initials: K
authors.lastname: Hayashi
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6; Department of Medicine, University of British Columbia, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6.
authors.forename: M-J
authors.initials: MJ
authors.lastname: Milloy
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6; Department of Medicine, University of British Columbia, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6.
authors.forename: Thomas
authors.initials: T
authors.lastname: Kerr
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6.
authors.forename: Huiru
authors.initials: H
authors.lastname: Dong
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6; Department of Medicine, University of British Columbia, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6.
authors.forename: Viviane Dias
authors.initials: VD
authors.lastname: Lima
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6.
authors.forename: Leslie
authors.initials: L
authors.lastname: Lappalainen
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6; Department of Medicine, University of British Columbia, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6.
authors.forename: Julio
authors.initials: J
authors.lastname: Montaner
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6; Department of Medicine, University of British Columbia, St. Paul's Hospital, 608-1081 Burrard Street, Vancouver, BC, Canada V6Z 1Y6.
authors.forename: Evan
authors.initials: E
authors.lastname: Wood
mesh_terms: D000328:Adult; D001955:British Columbia / Q000453:epidemiology; D002170:Canada / Q000453:epidemiology; D002423:Cause of Death; D015331:Cohort Studies; D016208:Databases, Factual; D005260:Female; D006801:Humans; D008297:Male; D008691:Methadone / Q000627:therapeutic use*; D008875:Middle Aged; D009294:Narcotics / Q000627:therapeutic use*; D058850:Opiate Substitution Treatment / Q000379:methods*; D009293:Opioid-Related Disorders / Q000401:mortality* / Q000534:rehabilitation*; D011446:Prospective Studies; D015819:Substance Abuse, Intravenous / Q000401:mortality* / Q000534:rehabilitation*; D014798:Vital Statistics
chemical_list: D009294:Narcotics; D008691:Methadone
keywords: Death; Injection drug use; MMT; Methadone; Mortality; Opioid maintenance treatment