A prior column presented an overview of the reduced risk of heart disease in women until after menopause. A common assumption is that after menopause, the replacement of hormones will protect women from the scourge of heart disease. Now there are reports that call that assumption into question
After menopause, hormone replacement therapy may be considered for reasons including slowing osteoporosis, maintaining supple skin and tissues, minimizing hot flashes, and perhaps maintaining healthy balances in some blood fats. The negative side of hormone replacement includes the risk of blood clots and increased risk of certain cancers if there is a strong family history of such malignancies. The assumption of hormonal protection from heart disease, suggested by observational studies, has been shaken by recent randomized clinical trials that suggest no benefit and possibly even harm. If you have been following these columns, you know that data from randomized clinical trials are more reliable to prove benefit.
What are the take home points of these studies? First, data generated are only valid in the populations examined. It is a reach to assume that information gathered in one set of patients are applicable to another set which may have different characteristics. The recent reports focused on older women with histories of heart disease. The question asked was whether hormone replacement prevented a second cardiovascular “event”. Using rigidly defined estrogen and progesterone preparations, some researchers suggested no benefit from the hormones used. Some women actually had higher risks for forming blood clots. The news reports simply reported that hormone replacement therapy in women after menopause may not prevent cardiovascular disease. Great for selling papers, but more of a stretch than justified by the science.
Second, there are no available randomized clinical trials in younger women who have not had heart disease to test whether hormone replacement therapy protects them from having or delays the development of their first cardiovascular event. These data will be forthcoming in very large trials like the Women's Health Initiative sponsored by the National Institutes of Health. But we do not have that information yet.
Third, there is considerable controversy on what constitutes hormone replacement therapy. In these early reports, researchers used older estrogen and progesterone preparations in fixed dosages. Gynecologists today are using newer drugs in variable combinations and at lower dosages, depending on each patient's circumstances. Choices may even include non-hormone drugs that simulate estrogens.
Until we have information from applicable randomized clinical trials, we should be careful about what we read. Applying new information to individual patients is why practicing medicine is as much art as science.