JACKSONVILLE (Reuters) -- When the diet drug combination Fen-Phen was linked to heart valve defects last summer, many patients rushed to have echocardiograms (ECGs) performed to detect heart abnormalities. A new report now suggests that the risk of heart valve problems with the use of the diet drug may be lower than previously thought.
"There is no question that (drug-related valvular defects are) real, but I don't believe the prevalence is 30%. My guess is that it is somewhere between 2% and 8% of new valve lesions," reported Dr. Gerard Aurigemma, an echocardiographer and director of the hypertension unit at the University of Massachusetts Medical Center, Worcester, at the American Heart Association's conference on obesity and cardiovascular disease here.
The 30% figure was based on physicians' responses to the request by the US Food and Drug Administration for reports on symptoms of valve disease in patients who had taken fenfluramine, dexfenfluramine, or combinations of either drug, with phentermine.
So far there are no peer-reviewed studies. It is not clear that the 113 cases reported to the Food and Drug Administration were representative of the estimated 4.2 million people who were taking these drugs in 1997, Aurigemma said.
The problem is compounded by the relatively high prevalence of subclinical valvular regurgitation in apparently healthy people.
The best data suggest that the prevalence of mitral valve regurgitation in the asymptomatic population is about 11%, of which 93% is mild. Aortic valve regurgitation is seen in 1.2% of asymptomatic individuals and 79% of those cases are mild, Aurigemma said.
Dr. Neil Weisman of Georgetown University Medical Center, Washington, DC, reported at the recent scientific session of the American College of Cardiology in Atlanta, Georgia, that echocardiography showed no significant increase in valve disease among patients taking dexfenfluramine.
Aurigemma performed echocardiography on 42 users of dexfenfluramine, half of whom had been using the drug in combination with phentermine. Unlike in the Georgetown study, all 42 patients in the Worcester series had an echocardiogram before they started the antiobesity drugs.
"We thought that it was important to identify a cohort with a baseline, pre-drug echocardiography," Aurigemma said.
The 42 had taken the drugs for a mean of 166 days, compared with 71 days in the Georgetown study. Only 2 patients (4.8%) had new or worsened valvular disease and both had been taking the Fen-Phen combination.
One had a valvular abnormality on the baseline echo study, which progressed from mild to moderate regurgitation. The other patient developed mild regurgitation, Aurigemma said.
Most individuals with valvular regurgitation have a benign course. But the drug combination Fen-Phen, when taken for prolonged periods, appears to predispose people to valvular disease, he said.
"I would extrapolate from that to say that, even if some develop mild aortic regurgitation develops it is unlikely that they will go on to need replacement," Aurigemma concluded.
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