Estrogen replacement therapy and the prevention of coronary heart disease in postmenopausal women

The use of estrogen replacement therapy (ERT) for the prevention of coronary heart disease (CHD) is discussed. Cardiovascular disease is the number one cause of death in women. It is believed that the loss of estradiol production at menopause increases the risk of CHD. Theoretically, ERT should decreases CHD rusk in postmenopausal levels the metabolic factors that affect CHD. Many mechanistic studies of the effects of estrogen on lipoproteins, hemostasis, carbohydrate metabolism, and vessel wall tone and reactivity support a cardioprotective role for estrogen. In addition, observational studies have found that ERT, with or without progesterone, significantly reduces the risk of CHD. However, mechanistic and observational studies can establish only an association, not a cause and effect relationship. Furthermore, bias may influence the risk estimates. The heart and Estrogen/Progestin Replacement Study (HERS), published in 1998, was the first large, randomized, controlled trial to evaluate the efficacy of estrogen and progesterone replacement therapy in reducing CHD risk. Overall, the study found that continuous hormone replacement therapy (HRT) in women with CHD did not reduce cardiovascular risk at an average of 4.1 years of follow-up. In addition, there was an early increase in the risk of thromboembolic events. Although many mechanistic and observational studies suggest that ERT reduces the risk of morbidity and mortality from CHD in postmenopausal women, the only large, randomized, controlled study of this question to date failed to confirm this. Until data from ongoing studies are available, health care providers must reconsider prescribing ERT or HRT solely for the secondary prevention of CHD.