Medical reversals: Oops! My bad!

Medical reversals refer to widely-used treatments that were later found to be harmful or useless. A new book, called Ending Medical Reversal, written by two doctors and published by Johns Hopkins University Press, aims to publicize and correct this problem. The problem, they say, is that treatments become accepted before robust data has proven their worth. At the moment, the authors say, we have a “near epidemic of medical reversals.”

A well-known example of a medical reversal is hormone replacement therapy for women. An initial study, involving 127,000 nurses between the ages of 30-55, compared women who took estrogen with those who did not. The results were stunning: those who used estrogen had 40 percent fewer heart attacks than women who did not. Based on this information, doctors wrote millions of prescriptions. Later, a randomized controlled study of 16,000 women between the ages of 50 and 79, came to the opposite conclusion. In this case, the women were randomly assigned to two groups, one of which was given hormone replacement therapy and the other a placebo. The study was halted three years early because the women receiving hormone replacement therapy were developing breast cancer, heart disease, stroke, and pulmonary embolism at a higher rate than those receiving a placebo.

Why the different results between the first and second studies? The first study merely kept track of the health outcome between a group of women who were already taking estrogen and a group who was not. It was not a randomized controlled trial. It turned out that those who were taking estrogen were healthier and wealthier to begin with (and did not smoke)—factors that skewed the results.

Of course, medicines, procedures, and devices are tested to some degree, but it is not uncommon for doctors to jump the gun, acting on hypotheses, case studies, observational studies, and lab results rather than on experimental results. What’s more, scientific papers are rife with faulty data, and many studies are deliberately designed by commercial interests to be deceptive. (A blog called “Retraction Watch” tries to keep track of all the scientific papers that have been retracted. In their first year, they found about 200 papers that were retracted because of errors.)

To make matters worse, studies have shown that it typically takes ten years for the medical community to abandon a practice that has been found to be useless or harmful. Pity the poor folks who gave up eating eggs for fear of raising their cholesterol (eggs do not raise cholesterol).

The book includes an appendix listing studies published in the New England Journal of Medicine between 2001 and 2010 that overturned a practice already in use—in other words, a reversal. There were 138 of these reversals in just this one journal!

Next week: Diet advice [yawn]

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