Hormones and heart disease in women: Heart and Estrogen/Progestin Replacement Study in perspective.

Despite the nearly universal finding from observational studies that postmenopausal estrogen therapy reduces the risk of CHD and the multiple plausible mechanisms by which estrogen might reduce the risk of CHD, hormone therapy had no benefit in the only large randomized clinical trial to date. Although it is possible that estrogen taken over the long term actually reduces CHD risk, it is not reasonable to begin the regimen used in HERS to prevent new or recurrent heart disease, given the observed excess early risk. Given the possible long term benefit, women who are already taking hormone replacement therapy may elect to remain on it. Women who are undecided should be asked to consider participation in clinical trials. The HERS has dramatically illustrated the need for them.