A recent report from the Framingham Heart Study may cool enthusiasm for using certain new tests—known as biomarkers—to identify people who appear healthy but may be vulnerable to developing a heart attack or stroke. The study asked, “How useful are these 10 biological markers for predicting death and major cardiovascular events in seemingly healthy individuals?” The answer, reported in the December 21, 2006 issue of the New England Journal of Medicine, was that using these newer tests, even in combination, added only moderately to assessments based on established risk factors. The 10 tests are listed in the table alongside well-established risk factors.
*The US Centers for Disease Control and Prevention offers more information on these and other risk factors for heart disease: http://www.cdc.gov/HeartDisease/risk_factors.htm.
Highlights
After following 3209 participants for up to 10 years, the researchers determined that the 10 lab tests were not much better than conventional data for predicting a healthy person’s risk of having a major cardiovascular event. The researchers defined a major event as any of these four things: myocardial infarction (a heart attack), coronary insufficiency (prolonged angina with documented electrocardiographic changes), heart failure, or stroke. An article in Journal Watch Cardiology noted that the study’s findings were consistent with those of another study (the ARIC study). A Washington Post article noted that the findings may not apply to minority groups because the study included almost all whites of European extraction.
Two of the tests, B-type natriuretic peptide (BNP) and albumin, predicted risk for cardiovascular events. The risk of having a heart attack, stroke, or heart failure was twice as great for those with the highest levels of BNP in their blood sample and albumin in their urine, compared to those with the lowest levels. Five of the tests, BNP, albumin, homocysteine, renin and C-reactive protein (CRP), predicted a person’s risk for death. The risk of dying during the study period was four times greater for those who had the highest levels of these five substances.
The researchers concluded that even when the most informative of these tests were used in combination (an even costlier screening strategy), their ability to predict outcomes “added only moderately” to predictions based on traditional risk factors.
Other Roles
Cardiac biomarkers have other uses. The researchers mentioned, for example, that some of these tests may be useful for those at intermediate risk or for certain subgroups. They also acknowledged that these tests may prove useful when combined with yet-to-be discovered biological markers.
Patients can “take heart” in knowing that traditional risk assessments for heart disease, including cholesterol tests, remain today’s most important screening tools. Whether any of these biomarker tests should be part of your primary care is a matter to discuss with your healthcare provider.
Sources
S1
Ability of biomarkers to predict risk of heart disease, stroke appears limited (press release). Massachusetts General Hospital. Available on the Internet: http://www.massgeneral.org/news/releases/122006wang.html. Accessed 11 Jan 2007.
S2
Johnson LA. Study casts doubt on new blood tests. Washington Post. 20 Dec 2006.
S3
Krumholz HM. 20 Dec 2006. Do newer biomarkers add prognostic value? Journal Watch Cardiology. Available on the Internet: http://cardiology.jwatch.org/cgi/content/full/2006/1220/2. Accessed 12 Jan 2007.
S4
NHLBI media availability: newer biomarkers predict cardiovascular risk but offer only modest improvement in risk prediction over established risk factors (press release). 20 Dec 2006. US Department of Health and Human Services, National Institutes of Health, National Heart, Lung, and Blood Institute. Available on the Internet: http://www.nhlbi.nih.gov/new/press/06-12-20.htm. Accessed 11 Jan 2007.
S5
Wang TJ, Gona P, Larson G, et al. 21 Dec 2006. Multiple biomarkers for the prediction of first major cardiovascular events and death. New England Journal of Medicine. 355;25:2631-2639.
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