Having hepatitis C virus (HCV) in addition to HIV is associated with an elevated risk of cardiovascular disease (CVD) compared with having only HIV. People with HIV already have as much as twice the risk of CVD compared with the general population.

Publishing their findings in the Journal of Viral Hepatology, researchers conducted a meta-analysis of four studies of people with HIV and hep C that examined CVD risk. The studies were all among adults and included populations of people in which none had experienced a CVD-related health event at the outset of the study period and a comparison group of people who only had HIV and not HCV.

All told, the four studies analyzed included 33,723 cohort members. The majority of the participants were men and the average age ranged between 36 and 48. Two of the studies were reviews of past medical data (retrospective) and two followed participants over time (prospective). The average follow-up time ranged between 2.3 and 7.3 years. The studies were conducted in the United States, Canada and Spain.

The study authors defined CVD as coronary heart disease, congestive heart failure and stroke.

Three of the four studies also found a statistically significant link between hep C and an increased risk of CVD among those with HIV, meaning the link is unlikely to have occurred by chance. The fourth study found an association that was not statistically significant, meaning the association may have been driven chance. In this new analysis, the researchers pooled all the results to come up with their own interpretation of the association.

After adjusting their data to account for differences among the participants, including sex, smoking, blood pressure, diabetes and LDL cholesterol, the authors of the new study found that having HCV as well as HIV was associated with a 24 percent increased risk of stroke and a 33 percent increase risk of heart attack, compared with having only HIV.

“More research is needed to further quantify this association, determine potential mechanisms that underlie this association and evaluate whether treatment for HIV and HCV infections can reduce CVD outcomes,” the study authors concluded.

To read the study abstract, click here.