title: The impact of methadone maintenance therapy on hepatitis C incidence among illicit drug users.
abstract: OBJECTIVE
  To determine the relationship between methadone maintenance therapy (MMT) and hepatitis C (HCV) seroconversion among illicit drug users.
  
  
  METHODS
  A generalized estimating equation model assuming a binomial distribution and a logit-link function was used to examine for a possible protective effect of MMT use on HCV incidence.
  
  
  METHODS
  Data from three prospective cohort studies of illicit drug users in Vancouver, Canada between 1996 and 2012.
  
  
  METHODS
  A total of 1004 HCV antibody-negative illicit drug users stratified by exposure to MMT.
  
  
  METHODS
  Baseline and semi-annual HCV antibody testing and standardized interviewer-administered questionnaire soliciting self-reported data relating to drug use patterns, risk behaviors, detailed socio-demographic data and status of active participation in an MMT program.
  
  
  RESULTS
  One hundred and eighty-four HCV seroconversions were observed for an HCV incidence density of 6.32 [95% confidence interval (CI) = 5.44-7.31] per 100 person-years. After adjusting for potential confounders, MMT exposure was protective against HCV seroconversion [adjusted odds ratio (AOR) = 0.47; 95% CI = 0.29-0.76]. In subanalyses, a dose-response protective effect of increasing MMT exposure on HCV incidence (AOR = 0.87; 95% CI = 0.78-0.97) per increasing 6-month period exposed to MMT was observed.
  
  
  CONCLUSIONS
  Participation in methadone maintenance treatment appears to be highly protective against hepatitis C incidence among illicit drug users. There appears to be a dose-response protective effect of increasing methadone exposure on hepatitis C incidence.
authors.affiliation: British Columbia Centre for Excellence in HIV/AIDS, St Paul's Hospital, Vancouver, Canada; Department of Medicine, Faculty of Medicine, University of British Columbia, Vancouver, Canada.
authors.forename: Seonaid
authors.initials: S
authors.lastname: Nolan
authors.forename: Viviane
authors.initials: V
authors.lastname: Dias Lima
authors.forename: Nadia
authors.initials: N
authors.lastname: Fairbairn
authors.forename: Thomas
authors.initials: T
authors.lastname: Kerr
authors.forename: Julio
authors.initials: J
authors.lastname: Montaner
authors.forename: Jason
authors.initials: J
authors.lastname: Grebely
authors.forename: Evan
authors.initials: E
authors.lastname: Wood
mesh_terms: D000328:Adult; D000437:Alcoholism / Q000453:epidemiology* / Q000534:rehabilitation*; D001955:British Columbia; D015331:Cohort Studies; D005260:Female; D006526:Hepatitis C / Q000453:epidemiology*; D006801:Humans; D013287:Illicit Drugs; D008297:Male; D008691:Methadone / Q000008:administration & dosage*; D058850:Opiate Substitution Treatment; D009293:Opioid-Related Disorders / Q000453:epidemiology* / Q000534:rehabilitation*; D011446:Prospective Studies; D000069078:Seroconversion; D019966:Substance-Related Disorders / Q000453:epidemiology* / Q000534:rehabilitation*; D055815:Young Adult
chemical_list: D013287:Illicit Drugs; D008691:Methadone
keywords: HCV; hepatitis C; illicit drug use; incident infection; methadone; opioid; seroconversion