Association of Opioid Agonist Therapy With Lower Incidence of Hepatitis C Virus Infection in Young Adult Injection Drug Users. Judith I. Tsui, MD, MPH; Jennifer L. Evans, MS; Paula J. Lum, MD, MPH; Judith A. Hahn, PhD; Kimberly Page, PhD, MPH JAMA Intern Med. 2014;174(12):1974-1981.
Injection drug use is the primary mode of transmission for Hepatitis C infection in the US, and younger, newer users of injection drugs are at increased risk for acquiring HCV with drug use. As prevention of infection remains the most feasible and cost-effective way to reduce mortality and morbidity from HCV, this study examined the effectiveness of maintenance opioid agonist therapy with methadone or buprenorphine as a method of reducing injection drug use and thus reducing the risk of HCV infection in young adults in San Francisco. Previous studies have suggested that opioid agonist therapy with methadone may reduce the incidence of HCV infection in older injection drug using populations, but little was previously known about the role of these treatments in the prevention of HCV in younger injection drug users in the era of buprenorphine.
This study involved collection of observational data from 552 injection drug users in San Francisco between 2000 and 2013. Participants included in the study all reported injection drug use within the month prior to study entrance, were younger than 30 years of age (with a median age of 23), were HCV negative at baseline screening, and were available to return for a minimum of 2 follow-up visits. Visits included quarterly interviews concerning demographic factors, risk exposures, injection practices, and preventative behaviors such as use of needle exchanges, as well as the collection of blood samples for HCV testing.
Based on participant self-report from quarterly interviews, participant groups were categorized according to those who were exposed to (1) substance use treatment in the past three months, including non-opioid agonist forms of treatment, (2) opioid agonist therapy with methadone or buprenorphine in either detoxification or maintenance therapy, or (3) no treatment. In this sample as a whole, rates of infection with HCV were found to be 25.1 per 100 person-years.
HCV infection rates were found to be more than 60% lower in participants who reported receiving recent maintenance opioid agonist therapy when compared with those who reported no treatment. However, HCV infection rates were not significantly different among groups that reported no treatment, those who reported recent non-opioid agonist forms of treatment, or those who reported opioid agonist detoxification (rather than maintenance) treatment. When results were adjusted for age, sex, race, baseline number of years of injection drug use, homelessness, and recent incarceration, only maintenance opioid agonist therapy was independently associated with significantly lower hazard rates for becoming infected with HCV over time.
These results support the conclusion that maintenance opioid agonist therapy rather than detoxification is a safer and more effective strategy for the prevention of serious medical complications of opioid addiction in young adult users. This study suggests that maintenance treatment with methadone or buprenorphine for opioid use disorders in young adults may be an important component of comprehensive strategies to prevent the spread of HCV infection in this injection drug user population, in which young adults are a major driving force in the HCV epidemic in the US and Canada and an important target for prevention strategies.