Abstract 16295: Yield of Screening for Coronary Artery Calcium in Middle Aged Adults Based on 10-Year Framingham Risk Scores: The Coronary Artery Risk Development in Young Adults Study
Introduction: High coronary artery calcium (CAC) burden is associated with high risk for coronary events, independent of the Framingham risk score (FRS). Some panels recommend widespread CAC screening in all but very low risk adults (i.e. those few with all optimal risk factor levels). In order to determine FRS levels where asymptomatic, middle-aged individuals could potentially benefit from CAC screening, we assessed the prevalence and distribution of CAC across FRS strata.
Methods: CARDIA is an NHLBI-funded cohort of young black and white men and women from 4 U.S. communities enrolled in 1985 to study the evolution of CHD. We included 2831 non-diabetic CARDIA participants with CAC measurement at the year 20 exam (ages 38–50 years, 53.2% women, 44.7% black). The number needed to screen (NNS; number of people that need to be screened to detect one person with CAC within each CAC category) was used to assess the yield of screening for CAC. FRS predicted 10-year risks were stratified as follows: 0–2.5%, 2.6–5%, 5.1–10% and >10%. Agatston CAC score was stratified by CAC >0 or ≥100. CAC prevalence across FRS strata was compared using χ2 tests.
Results: Any CAC (CAC >0) and high CAC burden (CAC ≥100) were present in 10.7% and 1.8% of participants, respectively (Figure). CAC prevalence and amount increased in higher FRS strata. CAC ≥100 was observed in 1.3%, 2.4% and 3.5% of those with FRS of 0–2.5%, 2.6–5% and 5–10%, respectively (NNS = 79, 41 and 29), but in 17.2% of those with FRS >10% (NNS =6). The highest NNS for presence of any CAC was 14, observed in the lowest FRS stratum (FRS 0–2.5%).
Conclusions: In this middle-aged non-diabetic cohort, the NNS for any CAC is fairly low in all persons, no matter the FRS. However, the yield of screening for high CAC burden (≥100) is low in those with FRS ≤10%. This is in agreement with most expert groups which recommend CAC screening only in intermediate risk (FRS 10–20%) groups.
- © 2010 by American Heart Association, Inc.