Why do medical opinions change often? Doctors explain


Sometimes it’s hard to tell the difference between replacement advice, which is issued when research improves on previous advice, and a complete reversal, which occurs because common medical practice has outstripped science and never actually worked or even caused any damage. Here are some examples of real medical flip flops in recent years.

  • Menopause hormones to protect the heart: In 2002, decades of advice on the heart benefits of menopausal hormones seemed to change overnight when a major study called the Women’s Health Initiative was halted after researchers detected more heart attacks in women taking drugs. hormones. In hindsight, doctors had misinterpreted the data from observational research. The current advice: Hormones can relieve symptoms of menopause but should not be used for chronic disease prevention.

  • Vioxx as a low-risk arthritis treatment: In 1999, the Food and Drug Administration approved Vioxx as a revolutionary pain reliever because it reduced the risk of gastrointestinal problems. But in 2004, Merck withdrew the drug because studies showed it significantly increased the risk of a heart attack.

  • Arthroscopic Surgery for Aging Knees: For years, partial removal of torn meniscus tissue has been the most common orthopedic procedure in the United States, with approximately 700,000 performed per year. In 2013, a researcher in Finland compared the operation to a “sham” procedure and found that there was no benefit. Most doctors now recommend physical therapy instead.

  • Megadoses of vitamins to reduce cancer and heart risk: For years, doctors believed that various vitamins could lower the risk of cancer and heart disease, but a number of studies have shown the exact opposite. A beta-carotene and vitamin A study found that supplements actually increased the risk of lung cancer in male smokers. A study on vitamin E and selenium, believed to protect against prostate cancer, increases the risk of contracting the disease.

  • Stents for stable heart disease: Doctors used to insert stents – tiny metal mesh tubes that support open arteries – into millions of otherwise stable patients with heart disease. One study found that the surgical procedure was no better than drug therapy for preventing heart attacks.

Dr Vinay Prasad, associate professor at the University of California at San Francisco, and Dr Adam S. Cifu, professor of medicine in the Department of Medicine at the University of Chicago, coined the term “medical reversal” and concluded that approximately 40 percent of routine medical practices that they have examined have been found to be unnecessary or harmful. In their book, “Ending Medical Reversal: Improving Outcomes, Saving Lives,” they noted that most of these failed treatments were initially adopted because they were based on logical reasoning.

“What is often behind the reversal: All of these things have a good story, they have a good pathophysiological rationale,” Dr. Cifu said. “They should be working. But things only work if they’ve been shown to work in people, and people are so complicated. “

While daily aspirin may reduce the risk of heart attack or stroke, it can also increase the risk of internal bleeding. Although the absolute risk of a bleeding event is relatively low, the risk increases with age.

Several experts say the New Preventive Services Task Force guidelines to reduce aspirin use are not a real medical reversal and should be seen as updated advice replacing outdated guidelines, which is why the panel exists in the first place. Earlier this year, the task force lowered the age of regular colonoscopy screening up to 45 years, compared to 50. The panel sparked an outcry several years ago when it recommended that women start breast cancer screening at age 50, instead of 40.

“The working group is constantly re-evaluating based on the available data,” said Dr. Barron H. Lernersaid a medical historian and professor of medicine at NYU Langone. “It can be seen as an about-face, but it’s really about adjustments based on the evolution of science. “

For people who have had a heart attack, stroke, or other major cardiovascular problem, the case for using aspirin to protect them from a second event remains strong. The new guidelines from the Preventive Services Working Group do not change this advice.

What has changed are the advice for using aspirin to prevent a first heart attack or stroke.

The first evidence to support aspirin to protect the heart came in 1988 from a randomized controlled clinical trial of 22,071 male physicians, some of whom took regular doses of aspirin. The study was stopped prematurely because the benefit in the aspirin group was so drastic – reducing the risk of heart attack by almost half.

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