Author + information
- Received June 28, 2010
- Revision received October 18, 2010
- Accepted November 1, 2010
- Published online May 3, 2011.
- Tochi M. Okwuosa, DO⁎,
- Philip Greenland, MD†,
- Hongyan Ning, MD, MS†,
- Kiang Liu, PhD†,
- Diane E. Bild, MD, MPH‡,
- Gregory L. Burke, MD, MSc§,
- John Eng, MD‖ and
- Donald M. Lloyd-Jones, MD, ScM†,⁎ ()
- ↵⁎Reprints requests and correspondence:
Dr. Donald M. Lloyd-Jones, Department of Preventive Medicine and Bluhm Cardiovascular Institute, Northwestern University, 680 North Lake Shore Drive, Suite 1400, Chicago, Illinois 60611
Objectives By examining the distribution of coronary artery calcium (CAC) levels across Framingham risk score (FRS) strata in a large, multiethnic, community-based sample of men and women, we sought to determine if lower-risk persons could benefit from CAC screening.
Background The 10-year FRS and CAC levels are predictors of coronary heart disease. A CAC level of 300 or more is associated with the highest risk for coronary heart disease even in low-risk persons (FRS, <10%); however, expert groups have suggested CAC screening only in intermediate-risk groups (FRS, 10% to 20%).
Methods We included 5,660 Multi-Ethnic Study of Atherosclerosis participants. The number needed to screen (number of people that need to be screened to detect 1 person with CAC level above the specified cutoff point) was used to assess the yield of screening for CAC. CAC prevalence was compared across FRS strata using chi-square tests.
Results CAC levels of more than 0, of 100 or more, and of 300 or more were present in 46.4%, 20.6%, and 10.1% of participants, respectively. The prevalence and amount of CAC increased with higher FRS. A CAC level of 300 or more was observed in 1.7% and 4.4% of those with FRS of 0% to 2.5% and of 2.6% to 5%, respectively (number needed to screen, 59.7 and 22.7, respectively). Likewise, a CAC level of 300 or more was observed in 24% and 30% of those with FRS of 15.1% to 20% and more than 20%, respectively (number needed to screen, 4.2 and 3.3, respectively). Trends were similar when stratified by age, sex, and race or ethnicity.
Conclusions Our study suggests that in very low-risk individuals (FRS ≤5%), the yield of screening and probability of identifying persons with clinically significant levels of CAC is low, but becomes greater in low- and intermediate-risk persons (FRS 5.1% to 20%).
- coronary calcium
- coronary heart disease
- Framingham risk score
- low risk
- number needed to screen
- risk factors
Supported by contracts N01-HC-95159 through N01-HC-95169 from the National Heart, Lung, and Blood Institute, Bethesda, Maryland. Dr. Greenland received an honorarium from GE/Toshiba in 2008. All other authors have reported that they have no relationships to disclose.
- Received June 28, 2010.
- Revision received October 18, 2010.
- Accepted November 1, 2010.
- American College of Cardiology Foundation