C-reactive Protein and Cardiovascular Disease

Based on the review of the published data, the CDC and the American Heart Association (AHA) have recommended the following guidelines for assessment of cardiovascular disease risk:

• CRP levels of 1 mg per liter or lower are considered low risk for cardiovascular disease.
  
  
• CRP levels of 1-3 mg per liter are considered moderate risk for cardiovascular disease.
  
  
• CRP levels greater than 3 mg per liter are considered high risk for cardiovascular disease.
  
  
• CRP levels greater than 10 mg per liter may suggest an acute coronary process, such as heart attack (acute myocardial infarction).

The known risk factors for cardiovascular disease are:

• high blood pressure (hypertension),
  
  
• diabetes mellitus,
  
  
• cigarette smoking,
  
  
• high cholesterol (dyslipidemia), and
  
  
• advanced age.

High c-reactive protein levels may predict a higher risk for cardiovascular disease alone or in combination with these other known predictors. Some studies have suggested an elevated risk for cardiovascular disease associated with elevated c-reactive protein levels even after correcting for the other risk factors.

A relation also seems to exist between an increased c-reactive protein level and the presence of known cardiac risk factors, such as advanced age, diabetes mellitus, elevated cholesterol, increased body mass index (BMI), obesity, and cigarette smoking. This may be possibly related to ongoing inflammatory atherosclerosis in these individuals because of their risk factors.

Despite these associations, research has not clearly and consistently established c-reactive protein as an independent risk factor for cardiovascular disease, as the data seem to be inconsistent from different studies. It has been proposed that elevated c-reactive protein is an independent predictor of atherosclerosis among healthy men and women.