C-Reactive Proteins and Systemic Disease

New Studies Suggest Inflammation Plays Key Role in Heart Disease, Underscores Link Between Periodontal and Heart Diseases

Two new studies published January 6, 2005 in the New England Journal of Medicine suggest that inflammation plays a key role in the onset of heart disease, and that reducing levels of a protein produced by the body during inflammation can be as effective as lowering cholesterol levels in preventing the risk of future heart disease.

The protein is called C-reactive protein (CRP), and it is manufactured in the liver, arterial walls, and elsewhere. For several years, physicians have used CRP levels to gauge inflammation in the body and acknowledged its role as a risk factor for future coronary troubles. Still, these papers are the first to show direct evidence that lowering CRP could lower cardiac risk.

In addition, the studies reassert the link between periodontal and heart diseases. In the past, several studies have indicated that periodontal infections can be correlated with increased levels of CRP. A study from October 2004, published in the Journal of Periodontology further found that 91% of patients with cardiovascular disease suffered from moderate to severe periodontitis, compared with 66% of non-cardiac patients. As early as September 2001, the American Academy of Periodontology had suggested that elevated CRP levels associated with periodontal disease could be a risk factor for cardiovascular disease.

One NEJM study, led by Paul Ridker, MD, of Harvard’s Brigham and Women’s Hospital in Boston, found that heart disease patients with the lowest levels of CRP in their systems were also the least likely to suffer a second heart attack. The second, led by Steven Nissen, MD, of the Cleveland Clinic, found that patients who lowered their CRP levels the most showed evidence of a relaxation of clogging in the arteries.

The medical community has responded to the studies with excitement, though some researchers caution that more work must be done before physicians can prove a causal link between CRP and heart disease. “These are important papers,” James Cleeman,MD, of the National Heart, Lung, and Blood Association told the New York Times last Wednesday, ”but we need to recognize that the relationship between CRP and heart disease is a developing story.”

Ridker believes the study’s implications will soon be readily apparent, telling WebMD the study will have “immediate clinical payoff.” “We believe we can save tens of thousands of lives immediately simply by making physicians understand that they need to monitor CRP levels in the same manner that they now monitor cholesterol levels,” he said.

The studies also suggest that statins could play an even larger role in the treatment of heart disease. Patients taking this cholesterol-fighting class of drugs also see reductions in their CRP levels. Nissen told WebMD that “about half the benefit of these drugs came not from lowering cholesterol, but from lowering CRP levels,” and that “if a patient has achieved target cholesterol levels on statins therapy but still have elevated CRP, then…[the patient] is only getting half the benefits.”

Sidney Smith, Jr., MD, a spokesman for the American Heart Association, told WebMD that “[doctors] need a better understanding of what therapeutic strategies work best in people whose CRP levels aren’t lowered by statins,” but also noted that the articles clearly indicated that CRP should be included in the tests used to monitor the condition of cardiac patients.

- DB