Estrogen Not Beneficial to Women with Heart Disease

The conventional medical wisdom surrounding estrogen has suffered yet another blow. A new study has confirmed the findings of a large 1998 clinical trial which found this hormone provides no heart-protective benefit to older women with heart disease. Both studies throw a cloud of doubt over the prevailing view among gynecologists that most women should be on long-term estrogen therapy after menopause to prevent heart disease.

The latest study, announced last month at a meeting of cardiologists, showed that estrogen did not slow the build-up of plaque in the coronary arteries of older women with heart disease. Over 300 older women with heart disease had been randomly assigned to take estrogen (Premarin), an estrogen-progestin combination (Prempro) or a placebo. Their coronary arteries were measured at the beginning of the study and again, four years later when the study ended. Doctors found that the hormones made no difference in the health of the arteries or in disease progression.

Similarly, a much larger clinical trial of 2,763 older women with heart disease had already shown that four years of hormone therapy failed to reduce their rate of heart attack or heart disease-related death (JAMA, 8/19/98). The findings came as a shock to many doctors because earlier observational studies indicate that estrogen-takers had a lower rate of heart disease than non-users. But observational studies are, by definition, inconclusive because they compare the rates of heart disease among women who chose to take hormones with those who did not. It has been well established that women who take hormones are in the middle-and upper-income bracket, and there's a lower rate of heart disease among such women irrespective of hormone use.

Only a large trial in which healthy older women are randomly assigned to take hormones or a dummy pill will determine the efficacy of estrogen in preventing heart disease. The Womens Health Initiative is just such a trial, and its results will be published in about five years.

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