Researchers led by Judith Hsia, MD, Professor of Medicine, George Washington University, Washington DC, United States, looked at the relationship between CEE use and the risk of clinical peripheral arterial events in healthy postmenopausal women.

The study enrolled 10,739 healthy women 50 to 79 years of age with prior hysterectomy who were participating in the Women's Health Initiative Estrogen Alone Trial. The women were randomized CEE 0.625 mg/day or placebo.

"The impact of unopposed estrogen on clinical peripheral arterial events has not been previously evaluated in a randomized trial," Dr. Hsia pointed out. "In two trials of conjugated estrogens combined with daily medroxyprogesterone acetate, no effect on clinical peripheral artery disease was identified in healthy postmenopausal women or those with coronary heart disease."

The trial defined peripheral artery disease as self-reported myocardial infarction or coronary revascularization. Incident peripheral artery disease was defined as overnight hospitalization with either symptoms or intervention, and was categorized as carotid artery disease, abdominal aortic aneurysm, or lower extremity arterial disease.

The analysis showed a trend towards increased risk of peripheral artery events in women taking CEE (hazard ratio [HR] 1.32).

The rate of carotid arterial events, lower extremity arterial events, and abdominal aortic aneurysm did not differ between treatment groups. However, the composite of lower extremity arterial disease/abdominal aortic aneurysm occurred more often in women on CEE (HR 1.63).

"Overall, the results show that unopposed CEE, like conjugated estrogens with medroxyprogesterone acetate, conferred no protection against peripheral artery disease," Dr. Hsia noted. "In fact, CEE increased the risk of lower extremity arterial disease/abdominal aortic aneurysm."

The 2004 guidelines for prevention of cardiovascular disease in women categorized unopposed estrogen as a class III intervention based on level C evidence (expert opinion, case studies, or standard of care), she said. The categorization of CEE as "not useful/effective and may be harmful" is supported by analyses of coronary heart disease, stroke, and peripheral artery disease in the Women's Health Initiative Estrogen Alone randomized trial, she added.


[Presentation title: Unopposed Conjugated Equine Estrogens and the Risk of Peripheral Arterial Disease. Abstract 1776]

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