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Watch for Weasel Numbers in Medical Studies


Ever wonder why so many medical studies discover spectacular benefits from new drugs? Maybe it's because researchers report the numbers in a way that makes them sound better than they should.

That's the concern of Dr. Jim Nuovo, professor of family and community medicine at the University of California at Davis. In a study published in the June 5 Journal of the American Medical Assn., Nuovo looked at 359 studies from leading medical journals and found that only 18 of them reported results in terms of absolute risk reduction. The rest reported only relative risk reduction--which can sound far more substantial.

Here's an example from Nuovo to explain the difference: Suppose an existing drug cuts the rate of heart attacks in men to 5%. A new drug cuts that risk to 4%. In terms of relative risk, that's an impressive-sounding 20% improvement. In absolute terms, however, there's only a one-percentage-point difference. The risk has gone from low to slightly lower--which doesn't sound very impressive, especially if the new drug costs 10 times as much as the existing drug.

Nuovo's point is that all of these numbers, and more, ought to be reported in every study. "There's no one number that explains everything in an article," he says. "Once you start putting things into context, you start getting a better picture." Proposed guidelines for clinical trials call for researchers to report absolute risk reduction along with relative risks, Nuovo says, but those guidelines are often ignored. Editors should require authors to follow them, he says. Nearly 30 years ago, scienentists at Iowa's Ames Laboratory helped improve sonar by concocting an alloy that produced louder and more dynamic "pings," to be heard more easily above the noise of a ship. Now, another set of Iowa scientists is bringing the material to the consumer with a gadget that can turn nearly any hard, flat, smooth surface into a speaker.

The key is something called Terfenol-D, made by Etrema Products of Ames, Iowa. It's a blend of iron and two rare-earth elements, terbium and dysprosium, known for their super-magnetic properties. When electricity is passed through the alloy, it changes shape, with movements powerful enough to vibrate a window, desktop, or file cabinet.

The first consumer product to use Terfenol-D was introduced on June 3. Called the Soundbug, it is a $49.99 device about the size of a computer mouse that can plug into a Sony Walkman or an MP3 player. When it's fastened by suction cup to a hard surface, the surface radiates sound.

Jon Snodgrass, chief scientist at Etrema, foresees other products. One idea is to embed Terfenol-D in the mouthpieces used by undersea divers. Radio signals would activate the alloy, which in turn would subtly vibrate the diver's jawbone, enabling him or her to hear outside messages. Two groups of researchers have devised new drugs for treatment of malaria that may be more effective and cheaper than existing medications.

One new class of drugs, synthetic peroxides, has been developed by the University of Nebraska Medical Center, Monash University in Australia, the Swiss Tropical Institute, and F. Hoffman-La Roche, as part of an international partnership called the Medicines for Malaria Venture (MMV). Such drugs work like a bomb that goes off when it's in or next to a malaria parasite, says Dr. Chris Hentschel, CEO of MMV.

Separately, Dr. Henri Vial of France's Montpellier University II has seen promise with a drug called G25, which may stop new outbreaks and be inexpensive to produce.

Malaria, a drug-resistant disease endemic in many poor regions, causes more than 1 million deaths a year, according to the World Bank. Researchers say the synthetic peroxides will be ready for human trials early next year, and G25 in two years. A 67-year-old woman was admitted to the hospital for treatment of cerebral aneurysms--weakened blood vessels in the brain. Doctors examined her and sent her to her room.

The next day, she was wheeled into cardiology, of all places, where a doctor had threaded a catheter into her heart before someone noticed he had the wrong patient. The procedure was stopped; the patient recovered.

In the June 4 Annals of Internal Medicine, Dr. Mark R. Chassin and Dr. Elise C. Becher of New York's Mount Sinai School of Medicine review this incident--which did not occur at Mount Sinai--and argue that mistakes like this need more attention. "Institutions underreport such procedures, and the medical literature contains no discussions about them," they write. "Of all the errors we make in delivering health care, this case surely represents one of the most disturbing."

Part of the problem here was that two patients had similar names. But Chassin and Becher found that 17 individual errors contributed to the mistake. The key to correcting the problem, they say, is better teamwork and communication--among hospital staff and with patients.


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