The impact of methadone maintenance therapy on hepatitis C incidence among illicit drug users

Addiction. 2014 Dec;109(12):2053-9. doi: 10.1111/add.12682. Epub 2014 Aug 14.


Aims: To determine the relationship between methadone maintenance therapy (MMT) and hepatitis C (HCV) seroconversion among illicit drug users.

Design: 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.

Setting: Data from three prospective cohort studies of illicit drug users in Vancouver, Canada between 1996 and 2012.

Participants: A total of 1004 HCV antibody-negative illicit drug users stratified by exposure to MMT.

Measurements: 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.

Findings: 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.

Conclusion: 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.

Keywords: HCV; hepatitis C; illicit drug use; incident infection; methadone; opioid; seroconversion.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Alcoholism / epidemiology*
  • Alcoholism / rehabilitation*
  • British Columbia
  • Cohort Studies
  • Female
  • Hepatitis C / epidemiology*
  • Humans
  • Illicit Drugs*
  • Male
  • Methadone / administration & dosage*
  • Opiate Substitution Treatment*
  • Opioid-Related Disorders / epidemiology*
  • Opioid-Related Disorders / rehabilitation*
  • Prospective Studies
  • Seroconversion
  • Substance-Related Disorders / epidemiology*
  • Substance-Related Disorders / rehabilitation*
  • Young Adult


  • Illicit Drugs
  • Methadone