Carotid Intima‐Media Thickness Score, Positive Coronary Artery Calcium Score, and Incident Coronary Heart Disease: The Multi‐Ethnic Study of Atherosclerosis

BACKGROUND Common carotid artery and internal carotid artery intima-media thicknesses (IMT) are associated with coronary heart disease (CHD) and increase with age. Using age, sex, and race/ethnicity IMT percentiles may improve CHD prediction when added to Framingham risk factors and coronary artery calcium score. We study these possibilities in the Multi-Ethnic Study of Atherosclerosis (MESA), a multi-ethnic cohort of whites, Chinese, blacks, and Hispanics. METHODS AND RESULTS IMT data were acquired in the age range 45 to 84 years. Common carotid artery and internal carotid artery IMT, sex, and race/ethnic specific normative values were calculated for each MESA participant and combined as an IMT score. Multivariable Cox-proportional hazards models and logistic regression models were generated with CHD as outcome adding the IMT score to (1) a base model with Framingham risk factors, sex, race/ethnicity and (2) the base model with coronary artery calcium added. Harrell's C-statistics and area under the curve were estimated. Median follow-up was 10.2 years (interquartile range: 9.7, 10.7 years) with 429 first-time CHD events. Mean age was 62.1 years and 52.6% of participants were women. IMT score increased the base area under the curve from 0.7210 to 0.7396 (P=0.0008) and with positive coronary artery calcium score added to the model, from 0.7627 to 0.7714 (P=0.02). CONCLUSIONS A carotid IMT score based on normative data incrementally adds to Framingham risk factors and a positive calcium score in predicting first-time CHD in an ethnically diverse cohort.