Hepatitis C virus (HCV) is associated with a higher risk of coronary artery disease, in which blood vessels that supply the heart muscle get narrowed or blocked, typically by plaque buildup.

Chinese investigators conducted a meta-analysis of 14 studies assessing the link between HCV and coronary artery disease. They found that having hep C, compared with the absence of the virus, was associated with a 25% increase in the risk of coronary artery disease.

The study authors also narrowed their analysis to exclude the cohort studies that were either retrospective (the researchers looked back at an earlier cohort of people) or prospective (the cohort was followed forward over time).

This left five case-control studies (observational studies in which people with the disease and those without are compared to search for factors associated with that disease) and one cross-sectional study (the participants were studied only at one time point). These two types of studies are considered to be in the middle of the hierarchy of study design in terms of the strength of evidence supporting their conclusions.

In the combined six studies, HCV was associated with a 94% increased risk of coronary artery disease.

However, treating hep C is associated with a reduced risk of cardiovascular disease overall, according to another recent study.