Tuesday, February 13, 2007

Two more heart disease risks to look out for

By Stephen Smith, Globe Staff

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. Today, researchers from Brigham and Women's Hospital, who've worked on the problem for more than a decade, present a more expansive detection model.

For the last 40 years, doctors have relied on five factors to evaluate a patient's risk of heart disease: their age, whether they smoke, blood pressure, total cholesterol, and levels of good cholesterol, known as HDL. But since that model was developed, heart specialists have refined their understanding of the biochemical and genetic roots of cardiovascular conditions.

In the Journal of the American Medical Association, the Brigham team asserts that the risk-scoring system they developed -- which adds two new risk factors, family history and a measure of inflammation -- does a better job of classifying some women's heart-disease risk. In some cases, risk went up; in others, 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 develop the new scoring method.

To determine if there was a more reliable way to predict heart disease, researchers collected an array of health data on more than 24,000 US 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. (Diabetics were not included in the study, because that single condition alone is considered to automatically predispose patients to coronary problems.)

Using sophisticated statistical analysis, the Brigham researchers sought to figure out 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, which researchers believe are critical in assessing heart-disease risk in men as well as women.

One was family history -- specifically, whether either parent of a woman suffered a heart attack before the age of 60. The other factor that mattered, according to the researchers, was something called C-reactive protein, a measurement of inflammation. Scientists increasingly recognize the important role inflammation plays in causing cardiovascular problems.

The resulting scoring system, called the Reynolds Risk Score. The method's name honors the major financial backer of the project, the Donald W. Reynolds Foundation, which specified that the research should focus on the cardiovascular health of women.

"I applaud what they've done," said Dr. Daniel Levy, director of the iconic Framingham Heart Study, which provided the basis for the risk-evaluation system now widely in use. "Providing additional approaches to risk assessment is an important step."

Using the health experiences of the women in the study as a yardstick, the Boston researchers compared the accuracy of their new risk-assessment test with the traditional method. More than 90 percent of the time, the two tests yielded similar assessments of risk.

But among women previously identified as being at a somewhat elevated risk of having a heart problem, the Brigham test reclassified as many as half of the patients.

Ridker is an ardent champion of measuring C-reactive protein. But it has proved to be a controversial test, with conflicting research on its value as a predictive measurement of 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 continue to receive royalties every time the test is performed.

Dr. C. Noel Bairey Merz, a heart specialist at Cedars-Sinai Medical Center in Los Angeles, said that before the new scoring system is widely accepted, it will need to undergo further validation.

"While this is a very encouraging, user friendly tool, I would like to see other people vet it," Bairey Merz said. "Is this really going to make a big difference, this particular score? That remains to be seen."

Stephen Smith can be reached at stsmith@globe.com.

Posted by Karen Weintraub at 07:21 PM

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