Methadone Maintenance Treatment Reduces Incidence of Hepatitis C Virus among People with Injection Drug Use

Methadone Maintenance Treatment (MMT) reduces behaviors associated with risk of blood-borne infections, but evidence for its impact on hepatitis C virus (HCV) incidence has been mixed. This analysis pooled data from 3 prospective cohort studies of people with injection drug use to examine seroincidence of HCV during semi-annual visits in relation to time-varying MMT enrollment status during the prior 6 months. Of the 3741 participants, baseline HCV prevalence was 63%. Of 1379 individuals who were HCV seronegative at baseline, 1004 (73%) had at least 1 follow-up HCV serology and were eligible for the current analysis. Median follow-up was 2.1 years, and 184 HCV seroconversions occurred for an incidence density of 6.3 per 100 person-years.

• Among the 55 (5.5%) participants receiving MMT at baseline, 14 seroconverted for an incidence density 0.48 per 100 person-years, compared with 5.8 per 100 person-years for those not receiving MMT.
• Among the 166 participants with MMT exposure at any follow-up visit, incidence density was 0.52 per 100 person-years, compared with 5.5 per 100 person-years among those with no MMT exposure. Those who reported MMT at 2 or more follow-up visits had an even lower incidence density (0.34 per 100 person-years).
• Multivariable models controlling for unstable housing, injection of various drugs, cohort of recruitment, and follow-up time confirmed that MMT had a protective effect against HCV seroconversion (adjusted odds ratio [aOR], 0.47). A similar protective effect was seen in participants aged ≤ 30 (aOR, 0.55).
• A dose-response effect of MMT exposure was found, with an aOR of seroincidence of 0.87 for each additional 6-month period of exposure.

Comments:

This study shows that, in addition to reducing opioid use, overdose, and HIV seroconversion the initiation and continuation of MMT reduces HCV seroconversion among patients with opioid use disorder. Although some clinicians are reluctant to recommend MMT to younger patients, the subgroup analysis of patients aged ≤ 30 suggests that we should be more aggressive in offering effective agonist therapy to younger patients who have not yet contracted HCV.

Peter D. Friedmann, MD

Reference:

Nolan S, Dias Lima V, Fairbairn N, et al. The impact of methadone maintenance therapy on hepatitis C incidence among illicit drug users. Addiction. 2014;109;2053–2059.