Taylor AJ et al. (2005) Coronary calcium independently predicts incident premature coronary heart disease over measured cardiovascular risk factors. J Am Coll Cardiol 46: 807–814

Coronary artery calcium (CAC) is linked to an increased risk of coronary heart disease (CHD), but the degree to which detection of CAC provides incremental risk prediction beyond contemporary measure is controversial.

In this cohort study, 2,000 healthy male and female US Army personnel aged 45–50 years were evaluated using measured coronary risk variables and CAC detected by electron-beam tomography.

The incidences of acute coronary syndromes and sudden cardiac death were recorded over a mean follow-up period of 3 ± 1.4 years. Coronary calcium was detected in 22.4% of men and 7.9% of women and was associated with an 11.8-fold increased risk of CHD in men. The study was not powered to detect a relationship between CAC and CHD in women. Overall, at a mean age of 46 years, 1.95% of men with CAC suffered from acute cardiac events compared with 0.16% of those without CAC (P<0.0001). The risk of coronary events increased incrementally with the degree of CAC. A family history of premature CHD was also predictive of incident events.

The marginal cost-effectiveness of introducing screening for CAC into a conventional risk-prediction assessment was projected to be US$37,633 per quality-adjusted life year, assuming 30% improvement in survival.

The authors conclude that, in young, asymptomatic men, “the presence of CAC provides substantial, cost-effective, independent prognostic value in predicting CHD.” Further studies including women and various ethnic groups are needed to extend these data.