| BLUERHYMER 2005-01-19, 2:11 am |
| Protein Power: The Role of CRP in Heart Disease
By: Christine Haran
People with normal cholesterol levels may feel like heart disease is not a
condition they need to worry about. But new research suggests that, when
figuring out their risk for heart attack, people also need to consider their
levels of a substance called C-reactive protein (CRP).
Two new studies, published January 6 in the New England Journal of Medicine,
show that lowering blood levels of CRP, a marker of inflammation in the body,
may help prevent heart attacks and heart-related deaths in people with heart
disease.
"This gives us evidence for the first time that CRP is not a bystander," says
Steven E. Nissen, MD, a Cleveland Clinic Foundation cardiologist who led one of
the studies. "CRP is not just associated with the disease, there appears to be
a cause-and-effect relationship."
The study led by Dr. Nissen and his colleagues revealed that low CRP levels
slowed the progression of artheroscerolosis, the build-up of plaque in the
arteries that leads to heart attack. In the study, high doses of
cholesterol-lowering statin drugs reduced both CRP and cholesterol levels,
helping researchers conclude that intensive statin therapy has an
anti-inflammatory effect.
The second study, led by researchers at the Brigham and Women's Hospital in
Boston, found that people with severe heart disease who had low CRP levels
after statin therapy had fewer heart attacks. Additionally, they were less
likely to die of heart disease than those with higher levels of CRP, whether or
not they had low levels of the so-called "bad" LDL cholesterol.
While the studies were conducted in people with heart disease, the findings
have some experts suggesting that certain people at risk for heart disease, as
well as those with heart disease, should have regular blood tests to measure
CRP levels. According to the American Heart Association (AHA), a CRP level of
less than 1 mg per liter is considered low risk; average risk is between 1 and
3 mg per liter; and a CRP of more than 3 mg per liter is high risk.
For some, the studies indicate that CRP level can help doctors and patients
make treatment decisions.
"There are a lot of individuals who fall just below the cholesterol guidelines
levels of risk that requires them to be treated," Dr. Nissen says. "If their
CRP levels are elevated, that would push me to try a statin drug. It also tells
me if I have a patient with borderline cholesterol who has a CRP of 0.5, maybe
I shouldn't treat them."
Cardiologist Richard Stein, MD, a professor of clinical medicine at Albert
Einstein college of Medicine in New York and a spokesperson for the AHA,
cautions that it is too early to base treatment guidelines on this finding.
"It would seem intuitive that reducing CRP is an important goal, but the
questions are 'Does one go on a statin to do that?', 'What are the risks?' and
'In whom are the risks worthwhile?'" he says. According to Dr. Stein, high
doses of statins have been linked to muscle breakdown, kidney failure and, in
rare circumstances, death. As a result, the risks and benefits of high-dose
statin therapy—which is needed to have an anti-inflammatory effect—should
be carefully evaluated.
"If I was faced with a patient with a low LDL but a CRP that was still high, I
would probably go up a notch with the statin," Dr. Stein continues. "Cardiac
risk is a global issue, so it is the sum of all risk factors and not a single
risk factor that affects heart attack risk." Other risk factors for heart
disease include smoking and levels of HDL cholesterol, the "good" cholesterol.
While the CRP's precise role in heart disease is still being figured out, an
awareness of it may help certain people avoid heart attacks—and will most
likely give health-conscious people one more thing to fret over.
Ask your doctor about CRP..
Published/Last Reviewed: January 13, 2005
|