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More from the WHI: Estrogen Alone for Women with Hysterectomy

The findings suggest that estrogen alone should not be used for chronic disease prevention, although it might have a role in treating symptoms in women who have undergone hysterectomy.

The objective of the estrogen-only arm of the Women's Health Initiative (WHI) was to assess the effect of conjugated equine estrogen (CEE) on incidence rates of common chronic diseases in postmenopausal women who had undergone hysterectomies.

A total of 10,739 women (age range, 50-79) were randomized to receive CEE (0.625 mg daily) or placebo and were followed for an average of 6.8 years. Because CEE had no effect on coronary heart disease (the primary outcome) and significantly increased risk for stroke, the NIH decided to terminate the study early. A trend toward increased risk for venous thromboembolism was noted in the estrogen group. However, estrogen use significantly decreased risk for hip fracture, and, contrary to most previous findings, a trend toward decreased breast cancer incidence was observed. CEE use had no significant effect on an index that combined overall risks and benefits. Of note, almost 54% of women had stopped taking their medication by the time the study was terminated.

Comment: This component of the WHI suggests that estrogen alone should not be used for chronic disease prevention in postmenopausal women; however, estrogen alone appeared to confer less long-term risk than did combination therapy in previously published results (Journal Watch Jul 26 2002).

A role still exists for estrogen in short-term treatment of symptoms of estrogen deficiency in women without uteri. In women with uteri, therapy with estrogen alone -- even for only a few months -- promotes endometrial hyperplasia. Other results now suggest that addition of progestin for 2 weeks at 3- to 4-month intervals will protect against hyperplasia, but additional research is needed to assess the risks of such a regimen.

— Robert W. Rebar, MD

Published in Journal Watch General Medicine April 27, 2004

Citation(s):

The Women's Health Initiative Steering Committee. Effects of conjugated equine estrogen in postmenopausal women with hysterectomy: The Women's Health Initiative randomized controlled trial. JAMA 2004 Apr 14; 291:1701-12.

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