URMC Cardiologist Leads National Panel on CRP Testing
Experts Issue Report Limiting New Blood Test for Heart Disease
January 28, 2003
A team of the nation’s leading authorities on heart disease say there is no need for the entire adult population to have their blood screened for C-reactive protein, an inflammatory marker that has been widely promoted as a good indicator of risk of heart attacks, sudden death or arterial disease.
The report is published in today’s issue of Circulation: Journal of the American Heart Association. Lead author and co-chair of the panel that crafted the recommendations is Thomas A. Pearson, M.D., Ph.D., senior associate dean for clinical research at the University of Rochester Medical Center. The recommendations for limited use of the new blood test, (hs-CRP test), follow months of speculation about the value of measuring C-reactive protein.
Many Americans are asking their doctors for the test, Pearson says, although no specific guidelines have been given until now. This is due to recent publicity of scientific studies showing that increased concentrations of CRP appear to be associated with risk of disease.
But the panel concludes that hs-CRP testing is not yet in the same category as cholesterol screening or high blood pressure screening. They emphasize that doctors should continue using other, well-recognized means of detecting heart disease, and encouraging their patients to quit smoking, eat right and make other healthy lifestyle choices.
“This new test should be used after the major risk factors such as high blood pressure and high blood cholesterol are already measured, and the physician would like more evidence for or against intensive management of those risk factors,” Pearson says.
Among other things, Pearson and the panel note, there is no evidence that making a treatment decision based on CRP improves survival. More investigation is needed into the possible link between CRP and cardiovascular disease, and whether reductions in CRP levels correlate with reduced risk of disease. Also, current science has focused on measuring “normal” CRP levels in European and European-Americans adults, while little population data exists for CRP levels in African-Americans, Hispanic Americans, Native Americans, and persons of Asian or South Asian heritage, or children and young adults.
Here are some additional key findings: Hs-CRP tests should be given to metabolically stable patients who are infection-free. (Cost range: $20 to $120) Results should be expressed as milligrams/liter (mg/L) only. Cut-points are: low risk < 1.0 mg/L; average risk 1.0 to 3.0 mg/L; high risk > 3.0 mg/L. If the test reveals a level of > 10 mg/L, doctors should look for other sources of infection or inflammation. For patients who already have coronary artery disease, hs-CRP testing may predict future heart attacks. But current recommendations support very aggressive therapy regardless of this new test, so it has limited value. Hs-CRP test results might motivate patients with borderline risk to improve their lifestyles and comply with drug therapy, though this is unproven.
The Centers for Disease Control and Prevention and the American Heart Association sponsored the March 2002 workshop at which the panel began exploring the link between inflammatory markers and cardiovascular disease. Co-chair of the panel is George A. Mensah, M.D., chief of the cardiovascular heart program at the CDC. Mensah and Pearson emphasize that the recommendations could change as more and better studies are completed. # # #