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Phen-Fen May Pose Smaller Threat For Heart Valve Disease Than Originally Reported

BOSTON, MA -- Dec. 1, 1998 -- Dieters using the banned appetite suppressants fenfluramine and dexenfluramine have a lower risk of developing new heart valve lesions than previously reported, says a study published in today’s issue of the Annals of Internal Medicine.

Beth Israel Deaconess Medical Center researchers found that only 4.3 percent of 46 patients who had echocardiography before taking the diet drugs developed valvular disease after using the medication for at least 14 days (five to six months on average). The United States Food and Drug Administration banned the use of the drugs last year when uncontrolled echo surveys found that as many as 38 percent of the patients on the drugs suffered valvular abnormalities.

"Patients in our study used diet medications for a shorter length of time compared to patients in some of the other studies and this might explain the lower risk of developing new or progressive valvular disease that we report," said the study’s lead author Christina Wee, MD, of the division of general internal medicine, Beth Israel Deaconess Medical Center. "In addition, because this current study examines the development of new or progressive disease after the use of medication, it may not be comparable to other studies which may have detected pre-existing but unrecognised disease of the heart valves."

The retrospective study examined the records and charts of patients who had undergone cardiac imaging with echocardiography before and after taking the diet medication, fenfluramine and dexenfluramine. Patients also were asked about their exercise tolerance and given a cardiopulmonary examination. For patients who declined the exam, data was abstracted using the most recent physician examination performed following therapy with the diet medications.

Of the 873 patients identified as users of the appetite suppressants, only 76 had undergone an echo before starting therapy. Of the 76 patients, 46 were eligible for the study, based on the study criteria. Two of the 46 patients developed valvular heart disease. Both had used Phen-Fen in combination. One patient already had valvular heart disease before taking diet medications. The worsening of the heart valve in this patient may have been unrelated to diet medication use. A second patient developed new valvular heart disease after use of Phen-Fen.

"Our results indicate that users of diet medications appear to be at lower risk for valvular heart disease than previously thought," the researchers wrote. “However, the risk is still substantial, especially in Phen-Fen users. Larger studies are needed to examine further the risk of short- and long-term use of diet medications."