What's the story with CRP?
DrRich:
My doctor recently checked a CRP test, and it was very
high. I had a stress test and echocardiogram, and they were normal. He
didn't have much advice for me except to take low-dose aspirin. I don't
smoke, and my cholesterol is normal. I exercise regularly, and maybe I'm a
little overweight, but not much. What do I do about this CRP? Should
I take antibiotics, or what?
Thanks, E.
DrRich replies:
Dear E.,
Elevated C-reactive protein (CRP) levels have now been validated as an independent risk factor for coronary artery disease.
The problem is, we don't really know what to do about those elevated CRP levels. First, CRP is an indicator of inflammation occurring anywhere in the body, so elevated CRP levels are not necessarily related to the heart. Second, CRP levels are considered by most to be a marker for increased risk, and not the cause of increased risk. So reducing the CRP levels, per se, may or may not turn out to be important.
There is some evidence that infection with an organism called Chlamydia pneumoniae may be related to coronary artery disease, and may also cause elevated CRP levels. But a study published in October, 2000 in Circulation failed to show any cardiac benefit when patients with serum evidence of Chlamydia were treated with antibiotics. So, for now at least, using antibiotics when CRP levels are elevated does not appear to be helpful.
There is also evidence that the statin drugs (drugs used to lower cholesterol) can reduce markers of inflammation (such as CRP), and studies have been started to see whether this effect is real, and whether it offers any clinical benefit. But for now, there is no real evidence that patients with elevated CRP and normal cholesterol levels should take statins.
The best way to use CRP levels is to consider them additional evidence for aggressively attacking the controllable risk factors for heart disease. If your cholesterol was borderline elevated, for instance, then a high CRP level might push you and your doctor in the direction of using statin drugs, whereas a low CRP level might stay your hand.
The problem comes when CRP levels are measured in people such as yourself - people with no outstanding risk factors that can be easily modified. What to do in people like you who have high CRP levels?
The answer is: nobody knows. Taking low dose aspirin (an anti-inflammatory agent) seems as good as anything. But obviously this is an unsatisfactory answer. The only good news is that there is a lot of research going on to figure out how to reduce the inflammation that participates in the progression of coronary artery disease (and that raises CRP levels). Within a few years, there should be a much better answer to your question.
In honor of your question, I have posted an article on CRP and fibrinogen, the new risk factors for coronary artery disease. Keep watching this website for breaking news on this topic.
DrRich
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