Coronary Calcium as a Predictor of Coronary. Events in Four Racial or Ethnic Groups. 

Background

In white populations, computed tomographic measurements of coronary-artery calcium
predict coronary heart disease independently of traditional coronary risk factors.
However, it is not known whether coronary-artery calcium predicts coronary
heart disease in other racial or ethnic groups.
Methods
We collected data on risk factors and performed scanning for coronary calcium in
a population-based sample of 6722 men and women, of whom 38.6% were white,
27.6% were black, 21.9% were Hispanic, and 11.9% were Chinese. The study subjects
had no clinical cardiovascular disease at entry and were followed for a median
of 3.8 years.

Results

There were 162 coronary events, of which 89 were major events (myocardial infarction
or death from coronary heart disease). In comparison with participants with
no coronary calcium, the adjusted risk of a coronary event was increased by a factor
of 7.73 among participants with coronary calcium scores between 101 and 300 and
by a factor of 9.67 among participants with scores above 300 (P<0.001 for both
comparisons). Among the four racial and ethnic groups, a doubling of the calcium
score increased the risk of a major coronary event by 15 to 35% and the risk of any
coronary event by 18 to 39%. The areas under the receiver-operating-characteristic
curves for the prediction of both major coronary events and any coronary event
were higher when the calcium score was added to the standard risk factors.

N Engl J Med 2008;358:1336-45.

Detrano and co-workers examined the predictive value of measurements of coronary-artery calcium using cardiac CT in a multiethnic U.S. population.
They found
a) that a doubling of the calcium score increased the estimated probability of both major coronary events (myocardial infarction and death from coronary heart disease) and any coronary event by approximately 25% during a median follow-up period of 3.8 years, and
b) The coronary calcium score contributed to the risk of both major events and any event in four major ethnic groups independently of other risk factors.

The measurement of coronary-artery calcium in this cohort added incremental value to the prediction of coronary heart disease over that of the standard coronary risk factors in each of four ethnic groups.