Researchers report high reinfection rates and attributable risk analysis suggest the existence of a subset of HIV-positive men who have sex with men with recurring sexual exposure to hepatitis C virus, which is troubling because HCV infections are more likely to become persistent and to lead to progressive liver disease in patients with HIV, including those on antiretroviral therapy.
According to the findings of a systematic review and meta-analysis published online on August 7, 2015 in AIDS, high reinfection rates and attributable risk analysis suggest the existence of a subset of HIV-positive men who have sex with men (MSM) with recurring sexual exposure to hepatitis C virus (HCV).
The study results—from researchers at New York University’s Center for Drug Use and HIV Research (CDUHR) at the College of Nursing (NYUCN)—are particularly troubling considering that HCV infections are more likely to become persistent and to lead to progressive liver disease in patients with HIV, including those on antiretroviral therapy. Unfortunately, the epidemiology of the incidence of sexually transmitted HCV infection in HIV-positive MSM has remained only partially understood.
“The purpose of our study was to explain why these outbreaks are occurring and understand whether the increase in reporting indicates a real trend,” said lead author, Holly Hagan, PhD, a professor at NYUCN and Co-Director of CDUHR who leads the HCV Synthesis Project. “Understanding the causes and the magnitude of the problem will help identify subgroups for targeted intervention.” Dr. Hagan and colleagues conducted the review and meta-analysis of studies characterizing the incidence of sexual transmission of HCV among HIV-positive MSM. The researchers made sure to exclude studies that incorporated MSM with a history of drug injection, in order to ensure that their review was limited to the sexual transmission of HCV.
The meta-analysis consisted of 13,000 HIV-positive MSM in 17 studies who were followed for more than 91,000 person-years between 1984 and 2012. The study investigators found a pooled seroconversion rate of 0.53 per 100 person-years.
“Putting this another way, if one thousand HIV-positive MSM were followed for one year each, approximately five would acquire HCV,” said Hagan. “This is far lower than the rates among [people who inject drugs]. However, when we pooled the data across studies and looked at incidence in relation to calendar time, we saw an increase.”
In fact, whereas the annual HCV incidence rate among HIV-positive MSM was estimated to be 0.42 per 100 person-years in 1991, the rate had increased three-fold, to 1.09 new infections per 100 person-years by 2010, and up to 1.34 per 100 person-years in 2012.
“If the trend continues, current incidence of HCV infections may be as high as 1.92 new infections per 100 person-years--meaning, were we to follow 1,000 members of this cohort over the next year, we'd likely find that approximately twenty acquired HCV,” noted Hagan.
Hagan and colleague also found that the rate of HCV re-infection following successful HCV treatment was 20 times higher than the rate to initial infection in the study population, at 11 re-infections per 100 person-years. Multiple reinfections were not uncommon in some study populations.
Unprotected, receptive anal sex and sex while high on non-injected drugs were associated with increased risk of HCV infection. Sex while high on methamphetamines was increased the risk of HCV infection 28.6-fold, when compared with sex while not high on these drugs.
“All of this data indicates the existence of a subgroup of HIV-positive MSM with recurring sexual exposure to HCV in whom the rates may begin to approach the risk of HCV infection among PWID,” said co-author Ashly E. Jordan, MPH, Associate Research Scientist and Project Director of the HCV Synthesis Project at CDUHR.
Looking ahead, the research team notes that additional studies are needed to gain a greater understanding of why these men are at particularly increased risk for HCV infection so that effective strategies can be developed to address the issue.
“Ideally, we'd like to see the development of an HCV prevention program for HIV-positive MSM that addresses both high-risk sex and drug use behavior,” said Hagan.