Chicago Tribune: Two weeks have passed since the startling disclosure that a common hormone replacement therapy, or HRT, for postmenopausal women does more harm than good. For many of the 13 million American women now using the drugs, that has meant two weeks of confusion, disappointment, sadness, frustration and anxiety. But the medical disclosure also has provoked a less-understandable emotion: anger.
Some critics have responded with vitriol that boils down to this: "Researchers knew for years that this drug (Prempro) was harmful, yet continued to push it on women. Once again greedy drug makers have used women as guinea pigs, exposing them to risks in order to make a buck."
This conspiracy theory reflects a naive understanding of how science works. Unsettling as the study results are, women have plenty of reason to be grateful for them. In ways long overdue, new research on issues related to the unique health issues of women is knocking down walls of ignorance about how their bodies work.
There were indeed prior indications that estrogen, especially when combined with progesterone, might increase a woman's risk for breast cancer. There were also numerous studies indicating those same hormones might reduce her risk of heart disease. Assuming that both of those assertions were true, many women gladly opted for protection against heart disease with a small additional risk of breast cancer. And for good reason: Heart disease and strokes kill 11 times as many women as does breast cancer.
The problem was, everything we previously knew about HRT in healthy women came from observational studies of women using the drug treatment, not from rigorously controlled experiments involving matched groups of users and non-users. The Women's Health Initiative was the first such thorough trial of long-term HRT use in healthy women. More than 16,000 women were randomly assigned to take either HRT or a placebo. The two groups of women were alike in every other way.
The study was designed to definitively answer a nagging question: Was it HRT that reduced the risk of heart disease -- or did healthier women who were at lower risk of heart disease in the first place tend to take HRT? Now we know, even if it's not the answer we were hoping for.
The randomized, controlled trial is the gold standard in evidence-based medicine. But it's also expensive and time-consuming. Most of what physicians do in their daily clinical practice is not evidence-based; it's what they have learned from their own experience and from the experience of their teachers, augmented by whatever research is available.
It's impractical for doctors to wait until they have unequivocal proof that a given treatment is beneficial over the long term. A lot of patients would die before we got evidence-based answers in every area of medicine. All clinicians can do is use their best judgment based on the knowledge available at any given time. As a society, however, we should be demanding precisely the kind of medical research exemplified by the Women's Health Initiative.