Is HRT indicated for the prevention of cardiovascular disease?

There is compelling evidence to suggest that estrogen administration to women of climacteric age reduces subsequent myocardial infarction by some 50%. Accumulating data also suggests estrogens confer substantial protection from stroke. Given this rationale, it is prudent to suggest to regulatory bodies that estrogen treatment would have this indication. Estrogens have other well-defined, and less well-defined, effects on various diseases; but observational studies suggest a decrease also in the overall mortality in estrogen users compared to nonusers. The critique of this concept is mainly that there is but one small clinical trial, and that observational data may be subject to confounders and biases. Questions have been raised whether the estrogen user comes from a preselected healthier population. Several of the observational studies are large enough to control for preexisting morbidity, including risk factors of cardiovascular disease. If anything, it would seem that women carrying risk factors inclusive of a sustained myocardial infarction are even better off (yielding a relative risk of 0.2) than those without risk factors. In order to protect the endometrium from malignant transformation and to ensure an acceptable bleeding pattern, a progestogen co-medication must be given with the estrogen. Observational data are based almost exclusively on estrogen-alone preparations, and concern has been expressed that progestogen addition may attenuate or even eliminate cardioprotection. Different estrogens at different doses, with different modes of administration, may also have an impact in this respect. The large variety of existing schedules for the administration of the progestogen adds to the difficulty in interpretation of the data with regard to cardiovascular disease.(ABSTRACT TRUNCATED AT 250 WORDS)