We already know that medication-assisted treatment of opioid addiction reduces the incidence of HIV. Indeed, people in active opioid addiction contract HIV six times more often than patients on medication-assisted treatment (Metzger et al, 1993). But previous studies haven’t shown clear reduction in the transmission of Hep C.
This new study does show a reduction in the incidence of Hepatitis C in opioid addicts who enter medication assisted treatment.
This prospective observational study by Tsai et al of 552 opioid addicts was done in San Francisco from 2000 to 2013. All subjects tested negative for Hep C in order to enter the study, and all were under thirty years old. These addicts enrolled in various forms of treatment: opioid agonist detoxification with methadone or buprenorphine, opioid agonist maintenance treatment with either methadone or buprenorphine, or non-opioid agonist forms of treatment. Some of the group elected not to get any form of treatment. Follow up testing for Hep C was done quarterly.
One-hundred and seventy-one study subjects tested positive for Hep C as the study progressed, giving an incidence rate of 25% per 100 patient-years. However, the study subjects who entered opioid agonist maintenance treatment were significantly less likely to become Hep C positive as compared to the addicts who got non-opioid agonist treatment or opioid agonist detox treatment. Addicts who enrolled in opioid-agonist maintenance treatment had a 60% reduction in the incidence of Hep C compared to the other study groups, which was statistically significant.
The patients on opioid agonist maintenance therapy had an incidence of 8.6 new cases of Hep C during 100 person-years of the study, while the group of subjects who entered non- opioid agonist forms of treatment, which included 12-step recovery and other abstinence-based forms of treatment, had an incidence of 17.8 over 100 person-years. People who didn’t get any treatment had an incidence of 28.2 per 100 person-years, while opioid addicts who underwent detox only had the highest Hep C conversion rate of 41% per 100 person-years.
As alarming and confusing as this last bit was, the data didn’t reach statistical significance, so we shouldn’t draw any conclusions about that bit.
Other studies have suggested a lower rate of Hep C transmission in opioid addicts who enter medication-assisted treatment, but none showed this as definitely as did this study.
Several things stood out to me as I read the study – first, these were young people. The average age was 23, and the study purposely excluded addicts over age 30. Maybe younger age means less time of exposure to Hep C. Older populations may already have Hep C.
This study looked at opioid addicts who sound like they are sicker than addicts I admit to treatment. For example, a whopping 69% were homeless. Do the homeless re-use needles at a higher rate? I don’t know, but perhaps homeless people have fewer resources to get clean needles, and could be at higher risk for Hep C than the rural inhabitants I treat.
The most common drug of use was heroin, used by 60% of the study population. While heroin has just started to invade my rural area, most of my new patients use opioid pain pills. It seems possible that intravenous heroin users have progressed further into addiction than pain pill users.
Even if the subjects in this study aren’t exactly the same as patients I see, this is good evidence that medication-assisted treatment reduces the risk of Hep C. It’s not the best reason for entering MAT; not dying from an opioid overdose is the best reason. But still, reducing the risk of Hep C is a good thing.