Abstract 2252: Gender Differences in the Incremental Risk of Coronary Ischemic Events Following First Atrial Fibrillation
Background: Whether atrial fibrillation (AF) confers additional coronary ischemic risk, beyond that measured by the Framingham risk equation, has not been studied.
Methods: The medical records for adult residents of Olmsted County, Minnesota, with an ECG-confirmed diagnosis of first AF between 1980 and 2000 were reviewed. We estimated the cumulative coronary ischemic risk at year 10 after first AF diagnosis in our cohort using the Framingham (Wilson version) coronary risk equation, and compared the findings to the Kaplan-Meier estimate of the actual incidence rate of coronary ischemic events in our cohort. We used Cox proportional hazards modeling to assess the sex-specific risk for first coronary ischemic events (angina with angiographic confirmation, unstable angina, non-fatal myocardial infarction, coronary death) following first AF development.
Results: Of the 2,768 subjects (mean age 71±16 years, 51% men) without coronary heart disease at AF diagnosis, we restricted our analysis to the subgroup of age 30 to 74 years (N=1,403) to be comparable with the age range that the Framingham risk equation was developed for. Based on the Framingham equation, the expected 10-year cumulative rate of coronary ischemic events was 21% in men and 11% in women. The actual observed Kaplan-Meier cumulative incidence rate of coronary ischemic events for our AF cohort was 22% (95% CI, 18 to 26) in men, and 19% (95% CI, 14 to 23) in women. Sex specific multivariable predictors of coronary ischemic events are shown in Table⇓ below.
Conclusions: AF confers additional risk of coronary ischemic events in women but not in men, independent of other conventional coronary risk factors. The underlying reasons for this gender difference in the impact of AF on subsequent coronary risk warrant further investigation.