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The impact of methadone maintenance therapy on hepatitis C incidence among illicit drug users
Author(s) -
Nolan Seonaid,
Dias Lima Viviane,
Fairbairn Nadia,
Kerr Thomas,
Montaner Julio,
Grebely Jason,
Wood Evan
Publication year - 2014
Publication title -
addiction
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.424
H-Index - 193
eISSN - 1360-0443
pISSN - 0965-2140
DOI - 10.1111/add.12682
Subject(s) - medicine , methadone maintenance , hepatitis c , seroconversion , incidence (geometry) , methadone , odds ratio , confidence interval , cohort , confounding , gee , generalized estimating equation , immunology , psychiatry , antibody , statistics , physics , mathematics , optics
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 V ancouver, C anada 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.