Last week’s American Heart Association meeting offered a few flare-ups in the debate over how to identify and treat people at risk of heart disease. Two studies raised questions about the usefulness of the C-reactive protein (CRP) blood test championed at Brigham and Women’s Hospital.
The HeartWire reports on a European study that looked at people without high cholesterol but with other risk factors for heart disease, like high CRP and high blood pressure.
Study co-chair Peter Sever of Imperial College in London, UK told the web site that “adding CRP to a conventional risk assessment…improved risk prediction, but not by much.”
“If you measure their total-to-HDL ratio, if you measure their blood pressure, if you’ve decided whether or not they smoke, [and consider] their age and their sex, that tells you all you need to know about their risk,” he said. “Putting CRP in there doesn’t alter the [risk-status] classification of people, and that suggests to me that it doesn’t have added value.”
That means CRP doesn’t have a practical role in deciding whether to initiate statin therapy, according to Sever.
Paul Ridker of BWH said not so. His research looked at a different group of patients – otherwise healthy people with no standard risk factors. From HeartWire:
“What they had in common was an elevated CRP, and clearly they benefited,” he said.“The whole issue with any biomarker is quite simple. The question you have to ask is, does the biomarker identify a population that wouldn’t otherwise be treated, and is there evidence that such a population benefits from therapy?”
In fact, findings from Ridker’s industry-funded JUPITER trial were strong enough to convince the FDA to expand the number of people who qualify for statin therapy.
Still, another study out of the AHA meeting concluded that many of the patients defined may not need statins. The yet-to-be published Johns Hopikins study found that, among patients with high CRP levels, those with calcium buildup in their blood vessels were much more likely to develop heart disease that those with no detectable buildup. Like CRP, the coronary artery calcium score is a measure some researchers believe identifies otherwise health people who are at risk for heart disease.
From MedPage Today:
CHICAGO — Physicians may be able to refine who will benefit most from taking statins by having patients undergo coronary artery calcium scans.
By adding the calcium score to the treatment work-up model, researchers here at the annual scientific sessions of the American Heart Association said that they could reduce the number of patients needed to treat to prevent one event to 19 people — lower even than the 25 to 50 number needed to treat described by the JUPITER investigators.
From the Hopkins press release:
“Our results tell us that only those with calcium buildup in their arteries have a clear benefit from statin therapy, and those who are otherwise healthy and have no significant calcification should with their physician focus on aggressive lifestyle improvements instead of early initiation of statin medications,” says study lead investigator Michael Blaha, M.D., M.P.H
So goes the battle over primary prevention — the use of drugs to prevent disease in healthy people. Some see the approach as a way to stave off illness. Others see primary prevention as a way for drug companies to push marginal medications on healthy people.
For more on the debate over CRP and heart disease see:
- Health News Review
- The New York Times
- BWH PR