Central  South  Dakota Medical News
The Clinical View
by P.E. Hoffsten, M.D.
1 August 2002

ESTROGEN REPLACEMENT THERAPY, REVISITED

      In the 1970’s, studies were done in large retirement centers to determine characteristics and health behaviors in retirement communities.   There were many important findings from these studies but there was one that stood out.  That was that women who used estrogen replacement treatment had a significantly decreased rate of heart attacks as compared to women that did not.  Two other similar publications at that time confirmed the initial observation that women who used estrogen replacement therapy had a substantial decrease in their rate of  heart attacks.  Note that these were so called primary prevention observations.  That is, the women in question had never had heart problems to begin with and the rate of development of  heart problems in women taking estrogen replacement therapy was less than the rate of  development of heart disease in women who did not.

       In the 1980’s and early 1990’s, so called “secondary prevention” trials were carried out to see if estrogen replacement therapy would reverse heart disease in women who already have the problem.  In the past month, the Journal of the American Medical Association has published the findings of the “HERS-II” study which addressed secondary prevention of coronary artery disease.  An additional publication the next week in the Journal of American Medical Association addressed the question of primary prevention of heart disease using estrogen in women who had no history of heart problems.  These studies seem once and for all to answer the question.  Specifically, estrogen replacement therapy has no beneficial impact to prevent heart disease in women who have already developed the problem or in women who have no known heart disease prior to starting estrogen.

       For several years, estrogen replacement therapy had been promoted as a treatment to prevent heart disease.  This was based upon the observational studies in retirement communities done in the 1970’s.  The nagging question on how to reconcile the new studies with the old is left unanswered to this time.  It is speculated that estrogen replacement therapy was something practiced by women who already had very healthy habits and was simply a marker for a healthier group.  These two studies would support that interpretation as opposed to the estrogen itself preventing heart attacks.

      A prospective study is one in which two groups are selected and matched before the test is ever done.  In a prospective study, the possibility of other factors can be controlled and the results are felt to be more reliable than an “observational study”.  In an observational study, an observation is made (women taking estrogen have fewer heart attacks) and then an explanation for the observation is looked for.  The obvious conclusion from the old observational studies would be that estrogen replacement therapy stopped heart attacks.  This conclusion is now not supported and appears to be false.  Observational studies provide a basis to ask questions but generally do not provide conclusive evidence to substantiate medical information.

       The question that might be asked is, “What do we do now?”  One conclusion that seems settled is that estrogen replacement therapy should not be started or continued simply to prevent heart disease.  Uncontested benefits of estrogen replacement therapy replacement include:
1.  Relief of hot flushes.
 2.  Avoidance of menopausal headache.
 3.  Avoidance of menopausal sleep disturbance.
 4.  Prevention of osteoporosis and hip fracture.
 5.  Avoidance of mood swings.

       Possible additional benefits that will be further evaluated by the Women’s Health Initiative include possible prevention of colon cancer, possible prevention of Alzheimer’s disease and possible of maintenance of skin health. On the downside, the question of whether estrogen replacement therapy causes or contributes to breast cancer is still being debated.  It would appear that there is a slight increase in the incidence of breast cancer in women taking estrogen replacement therapy.  Based on the Women’s Health Initiative, the control group of women taking no medication, had 30 breast cancers develop per year among 10,000 women.  The rate of women taking estrogen replacement therapy was 37 breast cancers for each 10,000 women taking estrogen replacement therapy for one year.  Depending on how you tally up these numbers, it can be noted that there are probably seven extra breast cancers in every 10,000 women taking estrogen replacement therapy.  If you listen to the media, television and the magazines, they will tell you there is a 25% increase in the breast cancer rate.  Both statements are correct.  One report spectacularizes the statistics.

       Lastly, the downside includes an increase incidence of gallbladder disease and an increased incidence of blood clots to the lungs called pulmonary embolism.  But to put the risks in perspective, there were 34 cases of blood clots developing in 1380 women treated with estrogen and 13 cases in 1380 women who were not treated with estrogen.  While the risk here is statistically significant, it is about one chance in 100 different.  If one perceives the benefits of estrogen replacement therapy are substantial, it must be weighed against this 1% risk of blood clots.

       One item of data that I have not seen mentioned by any TV commentator, any magazine writer, or any newspaper writer, was the observation that the death rate taking estrogen  replacement therapy, as opposed to women who are not, was exactly the same perhaps favoring women taking estrogen replacement therapy.  Inspite of the statistics showing that there is a slight increase in the incidence of heart attack, stroke, blood clots and breast cancer, in fact by the 7th year after the study was started, there was a lower mortality in the group of women taking estrogen replacement therapy than there was in the group not taking estrogen replacement therapy.

       Decisions on whether or not to use estrogen replacement therapy, are an individual consideration.  The comfort benefits from using this medication can be substantial.  The demonstrated risks are real although small considering the very large number of people examined.  The healthcare providers at your local clinics can help provide information and assist in decisions in whether estrogen replacement therapy is the right choice for the individual lady.