Hepatitis C increases risk of cardiovascular disease

Hepatitis C virus increases the risk of coronary artery disease, a large American study published in the 15^th July edition of Clinical Infectious Diseases (now online) has found. The study involved over 160,000 individuals, approximately half of whom were infected with hepatitis C. Despite having fewer risk factors for cardiovascular disease, the hepatitis C-infected individuals were more likely to have been diagnosed with coronary artery disease.

“This is the largest study to determine the role of hepatitis C virus infection in the risk if coronary artery disease”, write the investigators.

A number of infectious diseases, including HIV have been associated with an increased risk of cardiovascular disease. Many patients with HIV are co-infected with hepatitis C, and these individuals have a higher risk of early death from a number of causes than patients who are only infected with HIV.

Studies looking at the association between cardiovascular disease and hepatitis C have yielded conflicting results.

However, it is biologically plausible that hepatitis C may increase the risk of disease such as heart attack and stoke as hepatitis steatosis (fatty liver), a common complication of hepatitis C infection, has been associated with increased levels of inflammation and metabolic syndrome.

Investigators from the US ERCHIVES study, compared the risk factors and prevalence of coronary artery disease between 82,000 hepatitis C-infected veterans and 90,000 hepatitis C virus-negative veterans.

The individuals infected with hepatitis C had fewer traditional risk factors for heart disease and stroke than the uninfected patients. They were less likely to have high blood pressure (42% vs. 50%, p

Total mean cholesterol was lower in the hepatitis C-infected patients (175mg/dl vs. 198mg/dl, p

However, the hepatitis C-positive patients were significantly more likely to have liver problems (78% vs. 29%, p

Even though the individuals infected with hepatitis C had a lower prevalence of traditional risk factors for coronary artery disease, the investigators’ statistical analysis (which controlled for possible confounding factors) showed that the hepatitis C independently increased the risk of such diseases by 27% (adjusted hazard ratio, 1.27, 95% confidence interval: 1.22-1.31). Traditional risk factors for cardiovascular disease were also significant in both groups of patients.

A combination of factors including cytokine levels, increased levels of markers of inflammation, thrombosis, endothelial dysfunction, behavioural and social risk factors, malnutrition and liver problems are the likely to be the reason why patients with hepatitis C have an increased risk of cardiovascular disease, the investigators believe.

“In a comparison of hepatitis C-infected subjects with hepatitis C-uninfected control subjects, hepatitis C infection is associated with a higher risk of cardiovascular disease, even after adjustment for traditional risk factors”, conclude the investigators. “The reason(s) and mechanism(s) of this association need further study.”