Move by Crestor involves a misuse of test statistics

opinions

April 2, 2010 - 12:00 AM

Controversy in the medical community over a huge expansion in the use of a statin drug sheds interesting light on the use of statistics.
AstraZeneca, the manufacturer of Crestor, commissioned a study to determine if those not at risk of heart disease or stroke and had low “bad” cholesterol would benefit if they took a Crestor pill every day as a preventive.
A new test developed by Dr. Mark A. Hlatky, which measures the degree of inflammation in the body, has been approved by the Food and Drug Administration. Using the test’s criteria, an estimated 6.5 million Americans who have no cholesterol problems or sign of heart problems would benefit from taking the drug.
AstraZeneca plans to launch a new marketing program designed to sell Crestor to those millions of potential customers.
It will cite a clinical study of nearly 18,000 people which looked only at patients who had low cholesterol and an elevated level of inflammation in the body as measured by the test created by Dr. Hlatky, who led the study. Some of the patients were given Crestor, some a placebo sugar pill.
The study found a 55 percent reduction in heart attacks, a 48 percent reduction in strokes and a 45 percent reduction in angioplasty by-pass surgery.
The study was halted after 1.9 years because the results were so positive it was felt unethical to continue the trial and deny those on sugar pills a chance to take the statin.
But here’s rub. The patients in the study were so healthy that the rate of heart attacks was only .37 percent, or 33 patients out of the 8,901 who took a sugar pill. Among the Crestor pa-tients, it was .17 percent, or 15 patients of that 8,901. The difference turns out to be two of 1,000 people.
Dr. Steven W. Seiden, a cardiologist in New York, followed the experiment closely. He estimates that at $3.50 a pill, the cost of prescribing Crestor to 500 people for a year would be $638,000 to prevent one heart attack.
“The benefit is vanishingly small,” Dr. Seiden said. “It just turns a lot of healthy people into pa-tients and commits them to a lifetime of medication.”
He went on to note that the dramatic results produced by the test are “statistically significant, but not clinically significant.”

THIS DISTINCTION is an enormously valuable one to keep in mind in this day and age when everyone who watches television is constantly urged to “ask your doctor” if a prescription medicine “is right for you.”
Soon, perhaps very soon, Register readers will be urged to ask about Crestor even if they are healthy as a horse, have low cholesterol, low blood pressure and run 3 miles every day.
Those test numbers showing dramatic results will be trumpeted. But Dr. Seiden’s perspective is not very likely to be part of the commercial.
Those who fall for the pitch will be sending $3.50 a day to the industry, taking a chance on developing diabetes (one of the infrequent side effects of taking statins) and doing very, very little to improve their health.

— Emerson Lynn, jr.

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