Hormone replacement therapy and cardiovascular risk

Cardiovascular risk associated with hormone replacement therapy (HRT) has b een analysed by large epidemiological studies. This treatment has different effects depending on the type of vessel (venous or arterial) or site (hear t or brain). The several meta-analyses which have been published conclude t hat there is a significant decrease of about 30 to 50 per cent in ischaemic heart disease associated with HRT. In addition, oestrogen replacement ther apy is associated with a 25 per cent decrease in cardiovascular mortality. A recent meta-analysis has analysed the effect of HRT on cerebrovascular ri sk. A significant 20 per cent increase in ischaemic stroke associated with the use of HRT has been shown. However, a protective association of about 3 0 per cent has been observed in haemorrhagic stroke with HRT use. Recent ep idemiological studies have suggested an increased risk of thromboembolic di sease associated with HRT. The results of a randomized blind placebo-contro lled secondary prevention trial have recently been published. In this clini cal trial, women who receive oestrogen (0.625 mg conjugated equine oestroge n daily) plus progestin (2.5 mg medroxyprogesterone acetate daily) therapy did not experience a reduction in overall risk of non-fatal myocardial infa rction and cardiovascular heart disease death. This treatment also signific antly increases the rate of thromboembolic events. Other randomized trials of HRT for primary prevention are scheduled to yield results by 2000 or 200 5. All these studies have been conducted essentially in Anglo-Saxon countri es and have analysed the effects of conjugated equine oestrogens alone or c ombined with medroxyprogesterone acetate. This treatment is not currently u sed in France. But no randomized trials are under way with the HRT common i n France (transdermic oestrogen combined with natural progesterone). The ef fects of this treatment on cardiovascular disease remain unknown.