New Markers Won't Help Docs Assess Heart Risks

Blood levels of C-reactive protein, other markers, add little to known risk factors, study shows

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By Ed Edelson
HealthDay Reporter

MONDAY, July 10, 2006 (HealthDay News) -- Much-heralded blood markers such as C-reactive protein don't add much to older criteria such as cholesterol levels, obesity or blood pressure when it comes to gauging a patient's heart risks.

That's the main finding from a new report that throws doubt on the usefulness of C-reactive protein (CRP) in the diagnosis of cardiovascular risk.

"We measured C-reactive protein and 19 other so-called 'novel risk factors,' and we didn't find that they added significantly to what the conventional risk factors showed," said lead researcher Dr. Aaron R. Folsom, professor of epidemiology at the University of Minnesota, Minneapolis.

CRP, a marker of inflammation, has been touted by some researchers as a major indicator of the risk of heart attack, stroke and other cardiovascular problems.

Yet the new study of nearly 16,000 people followed for more than a decade found that blood levels of CRP added almost nothing to the predictions made by the traditional risk factors. The findings were published in the July 10 issue of the Archives of Internal Medicine.

The same was true of 19 other novel markers such as fibrin formation, B vitamin levels and antibodies to infectious agents, the report said.

"The result is a bit of a disappointment," Folsom said. "But it does support the use of the major risk factors that we know so much about."

There has been hope that CRP readings would be helpful in assessing people who were placed in an intermediate risk status --- not quite safe, but not in imminent danger, Folsom said. That idea has been argued back and forth and remains controversial, he said.

The study does show that "most patients won't benefit from measurements of C-reactive protein and these other things," Folsom said.

As for the other novel risk factors examined in the study, many of them are correlated with each other, so that measuring all of them would be redundant, he said.

Another expert wasn't surprised by the finding.

"I've been a C-reactive protein skeptic all along," said Dr. Donald M. Lloyd-Jones, assistant professor of preventive medicine and medicine at Northwestern University, co-author of an accompanying editorial. "I don't think it adds much to what we already know. If I see someone with a bad diet who is smoking and physically inactive, I don't need C-reactive protein to tell me the risk."

But there is "a very important take-home message that I would like to convey: That we have a remarkable ability [already] to predict on the basis of these known risk factors," he said.

The problem is that people in general and physicians in particular are doing "a pretty dismal job" of putting those risk factors to use, Lloyd-Jones said. Fewer than a third of Americans with adverse levels of risk factors such as obesity, high blood pressure high cholesterol and smoking have them under control, he said.

"Physicians are not necessarily identifying people at risk for coronary disease and not being as aggressive as they should be in taking preventive measures," Lloyd-Jones said.

People who do control their known risk factors not only reduce their risk of coronary disease but also have a lower risk for cancer and live longer, more useful lives, he said.

More information

Find out more about known cardiovascular risk factors at the American Heart Association.

SOURCES: Aaron R. Folsom, M.D., professor, epidemiology, University of Minnesota, Minneapolis; Donald M. Lloyd-Jones, M.D., professor, preventive medicine and medicine, Northwestern University, Chicago; July 10, 2006, Archives of Internal Medicine

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