Coronary artery calcium score improves CHD risk prediction

(HealthDay)—Inclusion of the coronary artery calcium (CAC) score improves coronary heart disease (CHD) risk prediction, while the absence of CAC reclassifies many patients as not eligible for statins, according to two studies published in the Oct. 13 issue of the Journal of the American College of Cardiology.

Robyn L. McClelland, Ph.D., from the University of Washington in Seattle, and colleagues derived and validated a novel risk score to estimate 10-year CHD risk using CAC and other traditional risk factors. The algorithm was developed in the Multi-Ethnic Study of Atherosclerosis (MESA) cohort involving 6,814 participants. The researchers observed significant improvement in risk prediction with inclusion of CAC in the MESA risk score (C-statistic, 0.80 versus 0.75; P < 0.0001). Evidence of very good discrimination and calibration was seen in external validation in two studies.

Khurram Nasir, M.D., M.P.H., from Baptist Health South Florida in Miami, and colleagues examined the implications of the absence of CAC in reclassifying patients from a risk stratum in which statins are recommended to one in which they are not. Data were included from 4,758 participants from the MESA cohort. The researchers found that for most of the 50 percent of participants eligible for statins, eligibility was due to having a 10-year estimated atherosclerotic cardiovascular disease risk of ≥7.5 percent. Forty-one percent of those recommended statins had CAC = 0. Of the participants eligible (recommended or considered) for statins, 44 percent had CAC = 0 at baseline.

"The absence of CAC reclassifies approximately one-half of candidates as not eligible for statin therapy," the authors write.

One author from the McClelland study disclosed financial ties to General Electric. Several authors from the Nasir study disclosed financial ties to the pharmaceutical, biotechnology, and technology industries.

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