High incidence of cardiovascular events in a rheumatoid arthritis cohort not explained by traditional cardiac risk factors

OBJECTIVE: To compare the incidence of cardiovascular (CV) events in persons with rheumatoid arthritis (RA) with that in people from the general population, adjusting for traditional CV risk factors. METHODS: Two hundred thirty-six consecutive patients with RA were assessed for the 1-year occurrence of 1) CV-related hospitalizations, including myocardial infarction, stroke or other arterial occlusive events, or arterial revascularization procedures, or 2) CV deaths. Both outcomes were ascertained by medical records or death certificates. For comparison, we used CV events that occurred during an 8-year period among participants in an epidemiologic study of atherosclerosis and CV disease who were ages 25-65 years at study entry. We calculated the age- and sex-stratified incidence rate ratio (IRR) of CV events between the 2 cohorts and used Poisson regression to adjust for age, sex, smoking status, diabetes mellitus, hypercholesterolemia, systolic blood pressure, and body mass index. RESULTS: Of the 236 RA patients, 234 were observed for 252 patient-years, during which 15 CV events occurred. Of these, 7 incident events occurred during the 204 patient-years contributed by patients ages 25-65 years, for an incidence of 3.43 per 100 patient-years. In the comparison cohort, 4,635 community-dwelling persons were followed up for 33,881 person-years, during which 200 new events occurred, for an incidence of 0.59 per 100 person-years. The age- and sex-adjusted IRR of incident CV events associated with RA was 3.96 (95% confidence interval 95% CI 1.86-8.43). After adjusting for CV risk factors using Poisson regression, the IRR decreased slightly, to 3.17 (95% CI 1.33-6.36). CONCLUSION: The increased incidence of CV events in RA patients is independent of traditional CV risk factors. This suggests that additional mechanisms are responsible for CV disease in RA. Physicians who provide care to individuals with RA should be aware of their increased risk of CV events and implement appropriate diagnostic and therapeutic measures.