Risk of myocardial infarction associated with chronic hepatitis C virus infection: a population‐based cohort study*

Hepatitis C virus (HCV) infection is associated with systemic inflammation and metabolic complications that might predispose patients to atherosclerosis. However, it remains unclear if HCV infection increases the risk of acute myocardial infarction (MI). To determine whether HCV infection is an independent risk factor for acute MI among adults followed in general practices in the United Kingdom (UK), a retrospective cohort study was conducted in The Health Improvement Network, from 1996 through 2008. Patients ≥18 years of age with at least 6 months of follow-up and without a prior history of MI were eligible for study inclusion. HCV-infected individuals, identified with previously validated HCV diagnostic codes (n = 4809), were matched on age, sex and practice with up to 15 randomly selected patients without HCV (n = 71 668). Rates of incident MI among patients with and without a diagnosis of HCV infection were calculated. Adjusted hazard ratios were estimated using Cox proportional hazards regression, controlling for established cardiovascular risk factors. During a median follow-up of 3.2 years, there was no difference in the incidence rates of MI between HCV-infected and -uninfected patients (1.02 vs 0.92 events per 1000 person-years; P = 0.7). HCV infection was not associated with an increased risk of incident MI (adjusted HR, 1.10; 95% confidence interval [CI], 0.67-1.83). Sensitivity analyses including the exploration of a composite outcome of acute MI and coronary interventions yielded similar results (adjusted HR, 1.16; 95% CI, 0.77-1.74). In conclusion, HCV infection was not associated with an increased risk of incident MI.