Stethoscope Proficiency and Fen/Phen

JAMA 1997;278:717-722


Researchers from the Allegheny University of the Health Sciences report in the Journal of the American Medical Association that physicians may not be very good at using stethoscopes to diagnose some heart problems. And the implications may be significant, especially with respect to the current hysteria about the diet drug combination "fen/phen."

The researchers studied 453 physicians in training and 88 medical students. Study participants were asked to identify 12 cardiac events recorded from patients.

Despite the multiple-choice format of the questionanaire, on average, the tested physicians recognized a mere 20 percent of all cardiac events. And the number of correct identifications improved little with year of training and was not significantly higher than the number identified by medical students. The researchers concluded:

In summary, our data show a disturbing inaccuracy in cardiac auscultatory skill among generalists in training. We chose cardiac auscultation because there is evidence this skill, competently performed, is a sensitive, highly specific, and cost-effective method of detecting valvular heart disease in asymptomatic subjects.

A shocking enough revelation in itself. But there's more.

Diagnosis of valvular heart disease can be made by using a stethoscope to listen for heart murmurs -- certain sounds made by malfunctioning heart valves. But not hearing heart murmurs with a stethoscope does not necessarily indicate an absence of valvular heart disease. According to the Merck Manual:

Of all the skills of a diagnostician, none is more difficult or demanding than auscultation of the heart, for it demands both excellent hearing and an ability to discriminate subtle differences in pitch and timing. Many very good physicians never acquire these skills because they do not possess the acute acoustic perception and discrimination, or they lose the skill through inadequate practice. Moreover, many have stethoscopes designed with everything in mind except auscultatory physics taken into consideration.

How does all this relate to the fen/phen hysteria?

It has been alleged the diet drug combination causes valvular heart disease. In July, a study published in The New England Journal of Medicine reported 24 cases of valvular heart disease in fen/phen users. But only 5 cases of valvular heart disease were confirmed (through surgery). Then in August, the Food and Drug Administration reported an additional 52 cases of valvular heart disease in fen/phen users. But these cases were not confirmed. So does this mean that fen/phen causes valvular heart disease?

Not yet.

First, the prevalence of valvular heart disease in health populations ranges from 1 percent to 6 percent. So among the millions of fen/phen users, there are bound to be quite a number with valvular heart disease (up to 60,000 per million otherwise healthy people) regardless of whether fen/phen increases the chances of valvular heart disease.

Second, it very well could be the 52 FDA-reported cases resulted from physicians--newly vigilant because of the July report-- who finally heard in their patients heart murmurs that had been there all along. Remember, physicians aren't necessarily all that great with stethoscopes to start with.

So the fen/phen hysteria may be much ado about nothing. And it is certainly premature to go into full-scale panic mode. But some already have. And click here for an article about the costs of the fen/phen hysteria to date.


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