Comparison of coronary artery calcification, carotid intima-media thickness and ankle-brachial index for predicting 10-year incident cardiovascular events in the general population

Aims: To compare the predictive value of coronary artery calcification (CAC), carotid intima-media thickness (CIMT) and ankle-brachial index (ABI) in a primary prevention cohort depending on risk factor profile to determine which of the three markers improves cardiovascular (CV) risk discrimination best in which risk group. Methods and Results: We quantified CAC, CIMT, and ABI in 3108 subjects (mean age 59.2 ± 7.7, 47.1% male) without prevalent CV diseases from the population-based Heinz Nixdorf Recall study. Associations with incident major CV events (coronary event, stroke, CV death; n = 223) were assessed during a follow-up period of 10.3 ± 2.8 years with Cox proportional regressions in the total cohort and stratified by Framingham risk score (FRS) groups. Discrimination ability was evaluated with Harrell's C. All three markers were associated with CV events (hazard ratio [95% confidence interval (CI)]: CAC: 1.31 (1.23-1.39) per 1-unit increase in log(CAC + 1) vs. CIMT: 1.27 (1.13-1.43) per 1 SD vs. ABI: 1.30 (1.14-1.49) per 1 SD, in FRS adjusted models). Considering reclassification, CAC lead to highest reclassification in the total cohort, while also for CIMT and ABI significant improvement in net-reclassification was observed [NRI (95% CI): CAC: 0.55 (0.42-0.69); CIMT: 0.32 (0.19-0.45); ABI: 0.19 (0.10-0.28)]. Conclusion: Coronary artery calcification provides the best discrimination of risk compared with CIMT and ABI, particularly in the intermediate risk group, whereas CIMT may be an alternative measure for reassurance in the low risk group.