It is a fact that has long frustrated doctors and their patients: Up to 20 percent of women who suffer heart attacks and other coronary problems had no obvious risk factors - no high blood pressure or elevated cholesterol. Other women who are told they're destined to experience heart problems never do.
That has left scientists hunting for a better method to gauge the risk of heart disease, which kills more women than breast cancer and lung cancer combined. This week researchers in Boston who have worked on the problem for more than a decade presented a more-expansive detection model.
For the past 40 years, doctors have relied on five factors to evaluate a patient's risk of heart disease: age, smoking, blood pressure, total cholesterol and levels of good cholesterol, known as HDL. But heart specialists have refined their understanding of the biochemical and genetic roots of cardiovascular conditions.
In last Wednesday's Journal of the American Medical Association, the team from Brigham and Women's Hospital asserts that the risk-scoring system they developed - which adds two risk factors - does a better job of classifying some women's risk of heart disease. In some cases, the risk went up; in others, the risk went down.
"This is important because we now have a simple and inexpensive way to correctly classify women's risk and, therefore, get the right drugs to the right women" to prevent heart disease, said Dr. Paul Ridker, the Brigham specialist who directed the effort.
To determine whether there was a more reliable way to predict heart disease, researchers collected an array of health data on more than 24,000 U.S. women 45 and older who had never experienced heart disease or cancer. Then they tracked them for an average of 10 years, recording whether they suffered heart attacks or strokes or required bypass surgery or other procedures to clear clogged arteries.
Using sophisticated statistical techniques, the researchers determined which of 35 potential risk factors most accurately forecast that women would have a serious cardiovascular problem. It turned out that the five historically important measurements were still relevant - but so were two others.
One was family history - specifically, whether either of the woman's parents suffered a heart attack before age 60. The other was something called C-reactive protein, a measurement of inflammation.
The resulting scoring system, the Reynolds Risk Score, is available online at www.reynolds riskscore.org. The method is named for the major financial backer of the project, the Donald W. Reynolds Foundation.
"I applaud what they've done," said Dr. Daniel Levy, director of the Framingham Heart Study, which provided the basis for the risk-evaluation system widely in use.
Using the women's health experiences as a yardstick, the Boston researchers compared the new technique with the traditional method. More than 90 percent of the time, the two tests yielded risk assessments. But among women previously identified as somewhat at risk, the Brigham test reclassified as many as half of the patients.
Ridker is an ardent champion of measuring C-reactive protein, but there is conflicting research on its value in predicting heart disease. The Brigham owns a limited patent on C-reactive protein tests - which cost about $8 to $12 a patient - and the hospital and Ridker receive royalties every time the test is performed.