CARDIOPROTECTIVE EFFECT OF HORMONE REPLACEMENT THERAPY IN POSTMENOPAUSAL WOMEN - THE EVIDENCE BIASED

Objective-To quantify the effect of selection of relatively: healthy w omen in studies reporting reduced relative risk for cardiovascular dis ease in postmenopausal women taking hormone replacement therapy. Desig n-Review of the follow up studies reported in three recent meta-analys es to determine the effect of oestrogen therapy on both total cancer a nd cardiovascular disease. The same standard statistical:methods as in the original analyses were used. Main outcome measures-Relative risks of total cancer and cardiovascular disease. Results-In most of the fo llow up studies the relative risk for total cancer was below 1. The st udies that showed the largest reduction in cardiovascular disease also showed the largest reduction in cancer, indicating a healthy cohort e ffect. Although heterogeneity within the studies prevented pooling, th e best estimate for the protective effect on total cancer was a relati ve risk of 0.83 among women taking oestrogen (95% confidence interval 0.71 to 0.96), while in the same studies the relative risk for cardiov ascular disease was 0.57 (0.50 to 0.64). Conclusions-Unintended select ion of relatively healthy women for oestrogen therapy may have influen ced the reported beneficial effect of oestrogen therapy on cardiovascu lar disease. It is unclear how much of the cardioprotection is due to this selection. Universal preventive hormonal replacement therapy for postmenopausal women is unwarranted at present.