Hormone replacement therapy and ischaemic heart disease among postmenopausal women

The beneficial effect of hormone replacement treatment (HRT) on osteoporosi s and menopausal symptoms has been well documented in randomised trials, bu t the impact of oestrogen-mediated metabolic changes on the risk of ischaem ic heart disease (IHD) is still debated. Randomised studies have shown that HRT increases levels of high-density lipoprotein cholesterol while causing a reduction in the levels of low-density lipoprotein cholesterol, serum fi brinogen, plasminogen activator inhibitor and homocysteine. In addition, HR T increases insulin sensitivity in both normoglycaemic and diabetic women. Unlike oral contraceptives, HRT has not been associated with an increase in arterial blood pressure, whereas a small increase in the risk of breast ca ncer and of venous thromboembolism appears to occur with both treatments. I nterestingly, some data suggest that oestrogen preparations may have differ ent effects on lipids. For instance, the beneficial effect on cholesterol m etabolism observed with oral conjugated oestrogen does not occur with trans dermal oestradiol, suggesting that the first-pass effect through the portal circulation may be necessary to achieve the full metabolic effect of oestr ogen treatment. Nevertheless, although a wealth of observational studies sh ow that HRT is associated with a significant reduction in morbidity and mor tality from IHC), the only randomised data available to date do not support these findings in postmenopausal women with established coronary artery di sease. J Cardiovasc Risk 6:105-112 (C) 1999 Lippincott Williams & Wilkins.