Hormone replacement therapy, cardiovascular and cerebrovascular disease

Historically, research into vascular effects of hormone replacement therapy (HRT) poignantly highlights the difficulties in extrapolating from medical research into clinical practice. Original observational trials encouraged great enthusiasm that HRT was protective against coronary heart disease (CHID) in post-menopausal women. This was supported by a plethora of beneficial mechanistic effects of HRT on the vascular system. In contrast, recent controlled trials have shown that a specific combined oral HRT actually causes a small increased risk of cardiovascular and cerebrovascular events, compared to placebo. The absolute risks were small, yet were accompanied by increased venous thrombosis and breast cancer. Although many controversies still remain regarding the vascular effects of specific types of HRT, currently, in my opinion, all HRT should be considered as causing a small increased risk of vascular events, until proven otherwise. However, the apparent lack of HRT effectiveness in the prevention of vascular disease should not deter enthusiasm for the use of established preventive therapies, especially lifestyle measures.