A study has produced powerful evidence that a simple blood test can spot healthy people who are at increased risk for a heart attack or stroke – and that giving them a widely used drug offers potent protection.
In findings that could transform efforts to prevent cardiovascular disease, the study of nearly 18,000 volunteers in 26 countries found that a cholesterol-lowering statin slashed the risk of those flagged by the test about in half – even if their cholesterol was normal.
“The potential public health benefits are huge,” said Paul Ridker of Brigham and Women's Hospital in Boston, who presented the findings at a meeting of the American Heart Association in New Orleans. “It really changes the way we have to think about prevention of heart attack and stroke.”
The test measures inflammation, reinforcing an increasingly accepted theory about the underlying biology of heart disease, which kills about 450,000 Americans each year.
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“It's a breakthrough study,” said Steven Nissen of the Cleveland Clinic, who was not involved in the research.
Several leading authorities predicted the findings would prompt many doctors to start routinely screening middle-aged patients for inflammation with the $20 test and begin prescribing the statin used in the study, or one of the less expensive generic versions, to those who get worrisome results. All statins reduce inflammation.
Some experts worried about rushing millions of healthy people onto powerful drugs. “This would be a huge expansion of the boundaries of drug therapy,” said Mark Hlatky of Stanford University. “I think we need to be careful before we radically change what we do. Nothing is risk-free.”
Traditionally, doctors believed heart attacks and strokes occur because high cholesterol causes fatty buildups to accumulate inside arteries supplying blood to the heart and brain. But about half of all heart attacks and strokes are in people with normal cholesterol.
Evidence has been building that inflammation, part of the body's defense against infection, may play a crucial role by causing plaques inside arteries to rupture, triggering blood clots that finally block blood flow. The blood test detects inflammation by measuring a substance in the blood called C-reactive protein (CRP), which statins drive down. But it had remained unclear how useful that information was.
In 2003, Ridker and his colleagues started prescribing either 20 milligrams of the statin Crestor or a placebo to 17,802 middle-aged and elderly men and women who had what are considered safe cholesterol levels but high CRP – 2 milligrams per liter of blood or above.
The researchers planned to follow the subjects for five years, but an independent panel monitoring the study stopped the trial in March after an average follow-up of less than two years, concluding that the benefit was so striking that it would unethical to continue withholding the real drug from those taking the placebo.
Compared with those getting the placebo, those taking Crestor were 54 percent less likely to have a heart attack, 48 percent less to have a stroke, 46 percent less likely to need angioplasty or bypass surgery to open a clogged artery, 44 percent less likely to suffer any of those events and 20 percent less likely to die from any cause, the researchers reported Sunday.
Ridker said one of his colleagues predicted that an estimated 250,000 heart attacks, strokes, angioplasties or deaths from heart attacks could be prevented in the United States alone over five years.
The study was funded by AstraZeneca, which makes Crestor, but the company had no influence over the analysis, Ridker said. He and his hospital receive royalties from the high-sensitivity CRP (hsCRP) test, but other researchers said that was no reason to doubt the findings.