ASK THE DOCTOR: CRP test not standard screening
By Dr. JIM MITTERANDO
The Patriot Ledger

Q. I have been reading a lot about the C-reactive protein test to predict heart disease. I asked my doctor about this test and she advised that I do not need it. What do you recommend?

A. Heart disease kills almost one million Americans each year - more than all cancer deaths combined. Many of these deaths occur because fatty, cholesterol-laden deposits (plaques) accumulate on the walls of the arteries (atherosclerosis), resulting in narrowed or blocked arteries.

As a plaque grows, the lining of the artery becomes roughened. A tear or rupture in the plaque may cause a blood clot that can block blood flow to the heart or brain resulting in a heart attack or stroke.

Cholesterol plays a role in atherosclerosis; but it is not the only culprit. In fact, ½ of all heart attack victims have normal cholesterol.

The new blood test, C-reactive protein (CRP) measures another possible atherosclerosis culprit - inflammation. Inflammation is the process by which the body responds to injury. Inflammation activates the immune system and plays a role in the healing process. But inflammation can go awry causing damage of blood vessels and making plaques more prone to clots. Recent studies suggest that a high CRP test may predict increased risk of heart disease.

Exercise, weight loss, quitting smoking and the cholesterol-lowering statin drugs (Lipitor, Zocor, Pravachol, Lescol) all reduce CRP and cholesterol.

The CRP test, though, has problems. First of all, it is not a specific test for heart disease. Increased inflammation occurs frequently with a viral illness such as a cold or flu. As a result, CRP can be falsely elevated if someone recently had an illness.

Secondly, there have been no studies yet to show that reducing CRP reduces heart disease or death.

In response to recent, frequent demand for the CRP test, the Centers for Disease Control and the American Heart Association issued guidelines recommending that the CRP test should not be used as a standard screening tool for the general public. This test may be useful in a subset of people who have moderate cardiac risk and borderline cholesterol levels to determine whether they should take a statin drug. (For example: someone with high blood pressure with mild to moderately elevated cholesterol).

People with coronary artery disease or who are at high risk for heart attacks do not need this test because they should already be taking a statin drug to lower cholesterol.

Despite the extensive press coverage that cholesterol and CRP testing receive, the most important factors that play a role in heart disease are still high blood pressure, diabetes, obesity, tobacco abuse and sedentary lifestyle.

If people were to lose weight, eat more fiber, exercise and stop smoking, they would do far more to prevent heart disease than taking a pill to reduce cholesterol or inflammation.

Dr. Jim Mitterando is a family doctor at Cohasset Family Practice and a staff member at South Shore Hospital in Weymouth.

Readers should send questions to: Ask the Doctor, The Patriot Ledger, P.O. Box 699159, Quincy, MA 02269-9159, or by E-mail to his attention at features@ledger.com.

Questions of general interest will be answered in this column. The information in this column is not intended to diagnose individual conditions, and individual replies are not possible. Readers should see their own doctors about specific problems.

Copyright 2003 The Patriot Ledger
Transmitted Tuesday, March 25, 2003