What was the objective of the study?
The Women's Health Initiative (WHI) study was a multi-center study that involved thousands of women from all over the country. The goal of the study was to answer the question: What can women do to stay healthy longer? The factors examined in the study were diet, exercise, calcium supplements, and hormone replacement therapy.
The press release about hormone replacement therapy that was issued the week of July 9, 2002 covered only one part of the study. This part of the study looked at women who have a uterus and were taking either Prempro (a specific estrogen and progesterone) or a placebo pill that contained no active hormone in it. The hypothesis for the study was that taking Prempro would result in a decrease in coronary heart disease. Secondary outcomes were breast cancer, stroke, venous thrombosis, colon cancer and fractures.
The WHI study is very different from most drug studies because it measured the long-term effects of the medication. Generally drug studies don't consider long-term health effects - but rather, look at immediate side effects and therapeutic value for a given disease. The idea of taking hormones to stay healthy longer is like taking vitamins to stay healthy - we want to be very sure that there is no harm being done. So the WHI study was set up to measure small effects over long periods of time. (Incidentally, this kind of information on vitamins or calcium is not available).
Why was the study stopped early?
Because the study was designed to see if hormone replacement therapy would help women stay heart-healthy longer, it was designed so that as soon as it became clear that the answer was "no," the study would be stopped. The study investigators agreed to stop the study if a 25 percent increase in breast cancer was demonstrated. This became evident after five years of follow-up, and so the study was stopped. A good way to understand the level of risk that was detected is to consider that if 10,000 healthy, postmenopausal women took Prempro for a year, there would be eight more cases of breast cancer among those women than among 10,000 women (0.08 percent/year) who did not take Prempro.
Looking at the data this way for the other outcomes, the 10,000 women taking Prempro would have eight extra strokes, eight extra pulmonary emboli, and seven extra coronary events. The women taking Prempro also would have six fewer cases of colon cancer and five fewer fractures. There were no differences in death from any cause between the two groups.
Does this mean that hormones are bad?
The results showed that the two products given to women in the study (Prempro, or conjugated estrogens plus medroxyprogesterone) should not be given to prevent heart disease, strokes, venous thrombosis or breast cancer. It does not mean that they are bad drugs or that they cause these diseases, but they may increase a woman's risk of developing these problems over time. The study also showed that the tested hormones were effective at preventing fractures and colon cancer.
Can I apply the results in a generalized way to any other hormone replacement products?
There is another part of the WHI study that has not been stopped. It looks at women who have had hysterectomies and are taking conjugated estrogen alone (no medroxyprogesterone). The data for these women do not, at this point, indicate excess risk. The data for these women will be released in 2005.
Should I stop taking hormones?
If you are taking Prempro therapy purely because you believe it will prevent heart disease, then you should stop taking it. If you are taking another hormone replacement product purely to prevent heart disease, you should talk to your physician.
If you are taking hormone replacement therapy to alleviate menopausal symptoms, this is still the most effective treatment. You may want to address the individual risks and benefits of continuing the therapy when you visit your healthcare provider each year.
If you are taking hormone replacement therapy to prevent osteoporosis and fractures, you should continue, because the WHI study clearly showed that women who took the hormones had fewer fractures.
Should I switch to another drug if I take Prempro, Premarin and Provera?
We don't know if the results of the WHI study will be the same with other forms of hormone replacement medications. We don't know if the adverse effects are caused by one of these drugs individually or by both of them. These questions are being investigated. At this time, this is a question that you should ask your healthcare provider. Remember that none of the adverse outcomes in this study happen in the short term. They happen after years of therapy. Take some time to discuss and consider this issue and then make a decision.
If I decide I want to discontinue hormones, how should I do it?
It is best to not stop all at once. You should taper off by taking your hormones every other day for a week, then every third day for a week, then stopping. You may still experience a recurrence of hot flashes and night sweats. These symptoms will most likely disappear over the next one to three months.
Reprinted with permission of OHSU Center for Women's Health 2002
View a summary of the study results
www.amwa-doc.org/healthtopics/hrt_breastcancer_qa.htm
www.whi.org
www.providence.org/oregon/programs_and_services/women_and_children/hrt.htm
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