The Women's Health Initiative (WHI) included two large clinical trials that evaluated whether hormone therapy with estrogen reduces the risk of coronary heart disease in postmenopausal women, according to background information in the article. In the part of the study designed to test estrogen therapy alone, 10,739 women aged 50 to 79 years who had undergone hysterectomy were assigned to take either conjugated equine estrogens--a mix of several estrogens--or a placebo. Though researchers had planned to study the women for 8.5 years, the estrogen-only trial was stopped in March 2004 after only 6.8 years because the hormone treatment appeared to increase the risk of stroke.
Judith Hsia, M.D., of George Washington University, Washington, D.C., and colleagues analyzed data from the estrogen-only portion of the WHI study. During the course of the trial, the women taking hormones experienced 201 coronary events, which included heart attacks and coronary deaths, while those taking placebo had 217 events. Overall, the risk was similar for women who took hormones compared with those who did not, though there was a suggestion of lower risk in women age 50 to 59 years.
Among these women (a total of 1,396) who were aged 50 to 59 years at the start of the study, there was no significant reduction in myocardial infarction (heart attack) or coronary death among those taking estrogen. However, coronary revascularization (reestablishment of blood supply to the heart) was less frequent among women taking estrogen, as were several combined endpoints, such as myocardial infarction, coronary death and revascularization. "This trial may have been unable to demonstrate a significant difference in the risk of myocardial infarction or coronary death by age group because of the low event rate in young women," the authors report.
(Arch Intern Med. 2006; 166: 357-365. Available pre-embargo to media at www.jamamedia.org .)
Editor's Note: The Women's Health Initiative was funded by the National Heart, Lung and Blood Institute, National Institutes of Health, Department of Health and Human Services, Bethesda, Md. Dr. Langer received honoraria from Solvay Pharmaceuticals, Houston, and served as a consultant for Berlex, Montville, N.J., and Monarch-King Pharmaceuticals, Bristol, Tenn. Dr. Prentice received an honorarium from Wyeth Pharmaceuticals, Madison, N.J., in 2004.
Archives of Internal Medicine