The controversy over estrogen replacement therapy: an update on clinical trials.

This is a review and presentation of recent clinical trials designed to ascertain the effects of estrogen or estrogen plus progesterone on the risks of heart disease. The framework of the epidemiologic evidence that estrogen is cardioprotective is reviewed and the impact of these data on apparent findings from clinical trials discussed. The Heart and Estrogen/Progestin Replacement Study is examined in detail, and the most frequent criticisms of its findings are presented. Findings from other clinical trials are presented and the clinical implications from the data discussed in relation to the larger body of literature pertaining to hormone replacement therapy and heart disease.