Recent injection drug use linked to HCV reinfection after DAA treatment

WASHINGTON — The risk for hepatitis C virus reinfection after direct-acting antiviral therapy was high in people with recent injection drug use, while antipsychotic drugs and opioid agonists offered possible protective effects.

“We saw in this study that younger [people who inject drugs (PWID)] had the highest rate of reinfection following [sustained virologic response]. This really highlights the importance of providing more support to this group to prevent reinfections,” Dahn Jeong, a PhD candidate at the School of Population and Public Health at the University of British Columbia and British Columbia Center for Disease Control, said at The Liver Meeting. “We also saw that treatment with antipsychotics was associated with reduced risk of reinfection among PWID. Lastly, [opioid agonist therapy (OAT)] was associated with lower risk of hep C reinfection, but we saw that it needs very high level of adherence and engagement, which may suggest more stability that protects against reinfection.”

Jeong presented an analysis of nearly 1.3 million individuals tested for HCV in the BC Hepatitis Testers Cohort, of whom 8,423 were treated with DAAs and achieved SVR. Of those, 20% (n = 1,658) had recent injection drug use (IDU) and 17% (n = 1,437) had past IDU.

Researchers monitored this group and identified 176 HCV reinfections over 11,807.6 patient years of follow-up for a reinfection rate of 1.49 per 100 patient years (PY). Reinfection rates were higher among those with recent IDU (n = 115; 4.39 per 100 PY) compared with those with past IDU (n = 24; 1.04 per 100 PY) or those with no history of IDU (n = 37; 0.54 per 100 PY).

“The incidence of reinfection is higher and increases at a steeper rate compared to the past or non-PWID,” Jeong said. “Year 2, almost 11% of the population had experienced reinfection and by year 5 almost 30% had experienced reinfection.”

Among individuals with recent IDU, reinfection rates were highest in those younger than 30 years (7.38 per 100 PY), those using opioids (4.93 per 100 PY) and those with HIV co-infection (5.45 per 100 PY).

“When looking at the factors associated with reinfection among recent PWID, we saw that younger age was associated with very increased risk of reinfection compared to the group that was between 50 and 59 years of age,” Jeong said. “The opioid use history was also associated with increased risk of reinfection. However, we saw that antipsychotic treatment was associated with a decreased risk of reinfection. So, we are seeing a protective effect of reinfection with antipsychotic treatment. ... People who received anti-psychotic treatment had over 50% reduced risk of reinfection compared to those who hadn’t received treatment among recent PWID.”

Those younger than 30 years had an adjusted HR of 3.26 (95% CI, 1.55-6.78) and those between ages 30 and 39 years had an adjusted HR of 2.06 (95% CI, 1.22-3.46). Opioid use also was associated with a higher reinfection risk (aHR = 2.03; 95% CI, 1.11-3.72), while receiving antipsychotic drugs lowered the risk (aHR = 0.44; 95% CI, 0.29-0.64).

Additionally, Jeong showed that interruption of OAT affected the reinfection rate. In those with less than a 5-day gap, there was only a 1% incidence of reinfection, while those with less than 2 days’ gap or no gap had no reinfection.

“The regular use maybe associated with a decreased risk of reinfection. However, long irregular use — meaning that there were many interruptions of OAT — was associated with higher risk of reinfection,” Jeong said. “With the increase in duration of OAT, there is a decrease of reinfection risk. So, we’re seeing a dose-response relationship of increased duration of OAT and more protective effect on reinfection.”