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Assessing Heart Attack Risk With Cholesterol, CRP

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At the New England Journal of Medicine's Web site:

If you're worried about a heart attack, you should already know your cholesterol level. But should you now ask your doctor for a blood test that measures C-reactive protein (CRP)?

CRP levels rise when there's inflammation somewhere in the body. That happens in a wide range of diseases, from arthritis to infections to cancer. And it may play an important role in cardiovascular disease.

Heart attacks and strokes occur when a clot blocks an artery in the heart or brain. Those clots are the endpoint in a long process of artery damage called atherosclerosis. That involves inflammation. So years ago, scientists started investigating to see if an elevated CRP level might be a warning sign of cardiovascular disease.

Some studies indicated it was. That led scientists to wonder if using a drug to lower high CRP levels would prevent heart attacks.

The results of the CRP studies launched a lot of controversy. Some claim that high CRP levels are better than high cholesterol or other established risk factors in predicting a heart attack. Others say knowing a person's CRP levels adds nothing.

Now a new study called Jupiter concludes that treating people who have low cholesterol but high CRP levels halved the risk of heart attack, stroke or cardiovascular death. The study was sponsored by AstraZeneca, which makes Crestor, the statin drug used in the research.

The results are sure to cause many doctors and patients to consider getting CRP tests — and, if the CRP level is high, to start using a statin to lower it.

Not so fast, some say. Dr. John Abramson, an instructor at Harvard Medical School, points out that the Jupiter study did not, in fact, find an overall difference in "any serious adverse event" between participants who took a statin drug and those who didn't.

"There was a reduction in cardiovascular events [in the group that took a statin], but that's apparently offset by other serious adverse events," says Abramson, author of a book called Overdosed America and a frequent consultant to plaintiffs who sue drug companies.

Experts and practicing physicians will probably debate the implications of the Jupiter study for months or years to come. Until the dust settles, another study being presented at this week's meeting suggests one strategy.

It found that high CRP levels improved doctors' ability to predict by 5 to 14 percent who would get a first-time heart attack or stroke. The study examined data from 3,000 participants in the ongoing Framingham Heart Study.

Authors of that study say doctors should first use the Framingham Risk Calculator to determine a patient's 10-year likelihood of a first-time heart attack.

If a patient comes out at "intermediate risk" — a 10-year likelihood of heart attack between 10 and 20 percent — then the study authors say doctors might want to consider measuring CRP.

If the CRP level is high, and if doctors and patients have done everything they can to modify the standard risk factors, they'll have to use their own judgment about whether to take a statin drug to lower their CRP and hope it will prevent a heart attack or stroke.

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