The impact
of hepatitis C on the incidence of cardiovascular events, including
stroke, was calculated from eight studies, combining data from 390,602
people and 18,388 events. Hepatitis C increased the risk of any event
modestly, by 30% (odds ratio 1.30, 95% CI 1.10-1.55, p = .002), and the
effect was similar when the analysis was confined to stroke alone (35%)
(odds ratio 1.30, 95% CI 1.03-1.82, p = .05). The risk was significantly
higher in studies where the background rate of diabetes was above 10%,
where the prevalence of high blood pressure was above 20% or where the
average age of the study population was above 50 years.
The authors note that even after allowing for the well-established
risk factors for heart disease – diabetes, high blood pressure and
smoking – the risk of death, cardiovascular disease and carotid artery
disease was still elevated in people with hepatitis C. Indeed, they
describe the effect of hepatitis C on cardiovascular risk as “especially
pronounced” in populations where diabetes, high blood pressure or
smoking are common.
The authors suggest that the metabolic abnormalities common in people
with hepatitis C may provide one explanation for the increased risk,
but they also point to recent evidence showing that hepatitis C promotes
inflammation, which contributes to the development of cardiovascular
disease.