July 10, 2006 -- Tests for C-reactive protein (CRP) don't help traditional risk factors identify people at high risk of heart attackand stroke, a long-term U.S. study shows.
Inflammation contributes to the formation of artery-clogging plaque and blood clots. People with a lot of inflammation have high CRP levels -- and are at increased risk of heart disease. For this reason, many doctors say CRP tests would help identify people with high heart risk.
But they don't, report University of Minnesota researcher Aaron R. Folsom, MD, MPH, and colleagues. Folsom's team analyzed data collected since 1987-1989 on nearly 16,000 Americans who were 45 to 74 years old at the start of the study.
CRP vs. Traditional Risk Factors
Folsom's team finds that traditional risk factors -- age, race, sex, total and HDL "good" cholesterol, blood pressure, blood pressure medications, smoking, and diabetes-- do a pretty darn good job of predicting heart risk. Adding CRP or any of 18 other proposed new heart risk factors doesn't make this evaluation better.
"CRP does not emerge as a clinically useful addition to basic risk factor assessment for identifying patients at risk of a first coronary heart disease event," Folsom and colleagues write in the July 10 issue of the Archives of Internal Medicine.
In an editorial accompanying the study, Northwestern University researchers Donald M. Lloyd-Jones, MD, and Lu Tian, ScD, agree that routinely measuring CRP isn't a good idea. However, they suggest that the test might be helpful in evaluating patients with borderline risk according to traditional risk factors.
And they note that while the traditional risk factors are very good at identifying people at risk of heart disease, they are not very good at motivating change. Fewer than one in three Americans at risk of heart disease succeeds in lowering his or her risk to a safe level.