Abstract 18337: Comparison of the Distribution and Predictive Value of Framingham Risk Factors and Coronary Artery Calcium for Major Coronary Events Between Asian (South Korean) and Framingham Cohorts

Abstract

Background: Coronary artery calcium (CAC) predicts major adverse cardiovascular events (MACE) beyond Framingham risk factors (RF) across multiple ethnic groups within the United States. However, its value in other, non-US populations is unknown. Methods: We prospectively obtained data on RF and MACE in asymptomatic adults from the registry-based ESCORT Study (4502 Koreans) and the population-based Framingham Heart Study (FHS, 3141 Whites), who underwent computed tomography to assess CAC. The primary composite endpoint of MACE included CV death, acute myocardial infarction and unstable angina with revascularization. We compared association of traditional RF and CAC with MACE in the two cohorts using multivariate Cox proportional hazard regression analysis, examining CAC both as a categorical variable using established cut-points and as a continuous variable using log 2 [CAC + 1]. We tested for interaction between ethnicity and CAC categories. Results: Over median 55 (ESCORT) or 60 (FHS) month follow-up, there were 95 MACE (ESCORT=45, FHS=50). ESCORT participants had greater prevalence of smoking, diabetes and hypertension (p<0.001 all) and greater 10-year Framingham risk score (11.4% vs 8.2%). In contrast, mean CAC prevalence and score were significantly lower in ESCORT (21.9%, 25.3 Agatston units, AU) vs FHS (41.5%, 99.9 AU). In ESCORT, more RF (age, male sex, systolic BP, HDL_C, diabetes) were predictive of MACE vs FHS (age only.) After adjustment for standard RF, doubling of CAC score (1-unit increase in log 2 [CAC + 1]) resulted in a 40% increase in risk of MACE in each cohort. Low CAC (1-100) was a significant predictor of MACE only in ESCORT but not in FHS (interaction p-value = 0.099.) Conclusion: There were significant differences in the burden and distribution of RF and CAC between Asian (South Korean) and white US (FHS) cohorts . CAC is a strong predictor of MACE in both cohorts, however lower CAC scores have greater predictive value in the Korean cohort.