Do Cholesterol Drugs Do Any Good?
John Carey at Business Week - in the majority of cases, apparently not, says Mr. Carey. So unless you have already suffered a heart attack, don't bother with Lipitor (or Mevacor or Zocor or Crestor or Pravachol). They'll lower your cholesterol numbers, but won't do anything else, except possibly impair your thinking, or your love-making. [lew]
For one thing, many researchers harbor doubts about the need to drive down cholesterol levels in the first place. Those doubts were strengthened on Jan. 14, when Merck and Schering-Plough (SGP) revealed results of a trial in which one popular cholesterol-lowering drug, a statin, was fortified by another, Zetia, which operates by a different mechanism. The combination did succeed in forcing down patients' cholesterol further than with just the statin alone. But even with two years of treatment, the further reductions brought no health benefit.
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Now do some simple math. The numbers in that sentence mean that for every 100 people in the trial, which lasted 3 1/3 years, three people on placebos and two people on Lipitor had heart attacks. The difference credited to the drug? One fewer heart attack per 100 people. So to spare one person a heart attack, 100 people had to take Lipitor for more than three years. The other 99 got no measurable benefit. Or to put it in terms of a little-known but useful statistic, the number needed to treat (or NNT) for one person to benefit is 100.
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Drug companies and other statin proponents readily concede that the number needed to treat is high. "As you calculated, the NNT does come out to about 100 for this study," said Pfizer representatives in a written response to questions. But statin promoters have several counterarguments. First, they insist that a high NNT doesn't always mean a drug shouldn't be widely used. After all, if millions of people are taking statins, even the small benefit represented by an NNT over 100 would mean thousands of heart attacks are prevented.
That's a legitimate point, and it raises a tough question about health policy. How much should we spend on preventative steps, such as the use of statins or screening for prostate cancer, that end up benefiting only a small percentage of people? "It's all about whether we think the population is what matters, in which case we should all be on statins, or the individual, in which case we should not be," says Dr. Peter Trewby, consultant physician at Darlington Memorial Hospital in Britain. "What is of great value to the population can be of little benefit to the individual." Think about buying a raffle ticket for a community charity. It's for a good cause, but you are unlikely to win the prize.
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If we knew for sure that a medicine was completely safe and inexpensive, then its widespread use would be a no-brainer, even with a high NNT of 100. But an estimated 10% to 15% of statin users suffer side effects, including muscle pain, cognitive impairments, and sexual dysfunction. And the widespread use of statins comes at the cost of billions of dollars a year, not just for the drugs but also for doctors' visits, cholesterol screening, and other tests. Since health-care dollars are finite, "resources are not going to interventions that might be of benefit," says Dr. Beatrice A. Golomb, associate professor of medicine at the University of California at San Diego School of Medicine.
