CRP itself doesn't cause heart disease. But now it's clear that CRP -- when measured with a high-sensitivity test -- helps identify people who can benefit from statin drugs.
An estimated 7.4 million Americans -- 4.3% of U.S. adults -- have CRP and cholesterol levels similar to those of patients in the JUPITER study.
What does this mean to you? Here are WebMD's answers to this and other questions.
What are statin drugs?
Statins include the prescription drugs Crestor, Lescol, and Lipitor. Three other statin drugs are available as brand name or generic drugs: lovastatin (original brand name, Mevacor), pravastatin (original brand name, Pravachol), and simvastatin (original brand name, Zocor).
Who takes statin drugs now?
If lifestyle change does not cut cholesterol, doctors may prescribe cholesterol-lowering drugs. Statins are the most popular of these drugs.
Doctors may prescribe statins for patients with LDL cholesterol levels lower than 130 if they have other factors that put them at high risk of heart disease. These factors include high blood pressure, diabetes, obesity, family history of heart disease, and personal history of heart disease.
What happened in the JUPITER study?
The JUPITER study enrolled nearly 18,000 apparently healthy men and women at a median age of 66. They did not have high cholesterol; their median LDL cholesterol level was 108. That's within the range considered "acceptable" by the American Heart Association.
However, these men and women had relatively high blood levels of CRP, a protein linked to inflammation. Inflammation plays a major role in cholesterol-linked narrowing of arteries and in the deadly bursting of cholesterol plaques in arterial walls.
Studies suggest that people with CRP levels higher than 3 milligrams per liter have more than twice the risk of heart disease as do people with CRP levels of 1 milligram per liter or lower. JUPITER study participants had a median CRP level over 4 milligrams per liter (and all had CRP levels of 2 milligrams per liter or higher).
Even so, under current treatment guidelines most doctors would not recommend statin treatment for such patients.
Half the study participants received the statin Crestor at a dose of 20 milligrams per day; the other half received an inactive placebo pill. After nearly two years, those taking Crestor had half as many serious cardiovascular events (heart attack, stroke, or death from heart disease or stroke) as those in the placebo group.
Risk was not large in either group. Over the two-year period, 1.8% of those in the placebo group and 0.9% of those in the Crestor group had a heart attack or stroke or died of heart disease or stroke. The difference is highly significant, and the safety board overseeing the trial called a halt to the study.
More people in the Crestor group than in the placebo group developed diabetes. It's not clear whether taking Crestor had anything to do with this.
Do the JUPITER findings apply only to Crestor?
Crestor was the only statin drug studied in the JUPITER trial. No similar studies have been completed for other statins.
All members of the statin family have similar modes of action. Some experts believe other statins will have benefits similar to those seen for Crestor in people with relatively low cholesterol levels.
Crestor is one of the strongest statin drugs in terms of its ability to lower cholesterol, but different patients do better with different statins.
I have low cholesterol. Why might I benefit from statins?
A person's cholesterol level is only one factor that contributes to heart disease. Many people have heart attacks despite having low cholesterol levels.
Statin drugs have many effects beyond mere cholesterol lowering. One of these effects is to lower inflammation, which plays a major role in heart disease. Not all the benefits (or risks) of long-term statin use are known, but the drugs clearly lower a person's risk of heart disease.
But the new findings may well change treatment guidelines. Doctors may now wish to order high-sensitivity CRP blood tests for patients with some risk for heart disease, even if they have low cholesterol levels. Relatively high CRP levels may convince patients -- and their doctors -- that it's time to start statin treatment.
It's not a simple decision. Once a person starts statin therapy, treatment usually continues for life. And while generic drugs cost less, treatment isn't cheap. Crestor, which is not available as a generic drug, costs about $3.45 per day.