Heart Tests For Biomarkers Add Little to Prediction, Treatment
Tests for the chemicals, called biomarkers, were studied because they have been linked to cardiovascular disease. Adding test results for six potential biomarkers of cardiovascular ailments to conventional predictors changed therapy for less than 1 percent of patients in the study, published in the Journal of the American Medical Association.
Many people who have heart attacks or strokes have one or none of the conventional risk factors including smoking, diabetes, and high blood pressure, according to background information in the paper. Researchers have been looking for better ways to predict risk for these people, and recently identified biomarkers, such as C-reactive protein, that were attractive candidates, said head researcher Thomas Wang, an assistant professor of medicine at Harvard Medical School.
“There are a lot of people who dont appear to be at high risk who have a cardiovascular event, and we want to know, how do you identify those people?” said Wang, the associate director of the heart failure service at Massachusetts General Hospital, in a telephone interview. “There doesnt seem to be a role for routine measurement of biomarkers.”
Heart disease causes about 27 percent of all deaths in the U.S., according to the Centers for Disease Control and Prevention. Its the number one killer worldwide, according to the Geneva-based World Health Organization.
Study Findings
The report described 5,067 Swedes who didnt have cardiovascular disease at the onset of the study. They were followed for more than 12 years, beginning between 1991 and 1994 and ending in 2006. During that time, there were 418 instances of heart attack, stroke, or death due to heart disease.
In addition to traditional risk factors, patients were also screened for six markers: C-reactive protein, n-terminal pro-B- type natriuretic peptide, cystatin C, lipoprotein-associated phospholipase-2, midregional proadrenomedullin, and midregional proatrial natriuretic peptide. Though five of the six biomarkers predicted future cardiovascular ailments, they werent much better than traditional risk factors.
Using the biomarkers together improved the accuracy “minimally,” and didnt change most peoples degree of risk, the authors wrote. Such risk factors can be used to guide a decision for preventive therapy such as cholesterol-lowering drugs or blood pressure medication.
“Its possible that biomarkers could be helpful in a subset of patients, patients about whom physicians are on the fence to treat,” Wang said. “But thats probably a pretty small population.”
Doctors who may have considered measuring biomarkers in everyone should feel reassured that such routine tests arent necessary, Wang said.