CAC Score Modestly Improves PREVENT ASCVD Risk Prediction

Adding coronary artery calcium (CAC) scores to the Predicting Risk of Cardiovascular Disease EVENTS–atherosclerotic cardiovascular disease (PREVENT-ASCVD) equations modestly improved overall risk prediction, with the most substantial reclassification among adults at borderline risk, according to a longitudinal observational cohort study published in JAMA. The study was motivated by the 2026 ACC/AHA/Multisociety Dyslipidemia Guideline, which recommends selective CAC scoring for adults with PREVENT-estimated 10-year ASCVD risk of 3% to <10% when treatment decisions remain uncertain.

The analysis included 6098 adults aged 45 to 79 years without ASCVD at baseline who participated in the Multi-Ethnic Study of Atherosclerosis at 6 US sites. Investigators compared 10-year ASCVD risk estimates from the PREVENT-ASCVD equations before and after CAC scores were added. Model performance for fatal and nonfatal ASCVD was evaluated using the Harrell C statistic, calibration, and categorical net reclassification improvement across low, borderline, intermediate, and high risk groups.

At baseline, participants had a mean age of 61.4 years, 52% were female, the mean estimated 10-year ASCVD risk was 6.4%, and 49% had a CAC score greater than 0. During 10 years of follow-up, 366 participants, or 6%, experienced an ASCVD event. The Harrell C statistic for the base equations was 0.73.

Adding CAC increased the Harrell C statistic by 0.02 (95% CI, 0.01-0.03), and the categorical net reclassification improvement was 0.095 (95% CI, 0.053-0.137). Among participants initially classified as having borderline risk, ASCVD event rates rose with CAC burden: 1.9% for a score of 0, 3.9% for scores greater than 0 but less than 100, 7.4% for scores of 100 to less than 300, and 14.3% for scores of 300 or greater.

Investigators concluded that adding CAC across all risk groups produced only modest overall improvement and, in some groups, did not change model discrimination or reclassification. The findings supported selective CAC use among people with borderline to intermediate risk estimated by the PREVENT-ASCVD equations.

Source: Huang X, Petito LC, Allen NB, et al. Predictive utility of coronary artery calcium score added to the PREVENT atherosclerotic cardiovascular disease equations. JAMA. Published online August 26, 2026. doi:10.1001/jama.2026.13233