When doctors rely on promise instead of proof

Doctors' love of a good story can be detrimental to your health.

There is one thing that costly, state-of-the-art medical technology and common sense, low cost medical interventions have in common: They either work or they do not.

In 2010, a Baltimore-area doctor was disciplined for placing hundreds of coronary stents — small expandable tubes — in patients who may not have needed them. Although this doctor could be seen as an outlier, and to some extent was, his practice patterns were not that far from the norm. Thousands of patients with stable angina have undergone coronary stenting, expecting it will prevent a heart attack. The truth is that it does not. Whether or not these stents even improve heart symptoms has been questioned. Stenting for stable angina is a high-tech and costly medical practice that does not work.

If you have asthma or rhinitis (a chronically runny nose) and are allergic to dust mites, zipping up your bedding in impermeable bed covers seems to make sense. It is a low cost way to keep dust mite allergens away. Yet, when you test these covers in a rigorous scientific study, they do not improve symptoms or other outcomes. Bed covers to keep dust mite allergy at bay do not work.

Coronary artery stents costs thousands of dollars and impermeable bed covers costs tens of dollars. Both were common medical practices that never worked. All of us have our biases: Some of us prefer natural, commonsense, low cost medicines; while others look to state-of-the-art, high-tech, and costly interventions. But there is no general rule in health care about what works. Of course, when medical practices fail, the more costly (in aggregate), the more invasive and the more harmful ones are the ones we regret the most — but, to some degree, we regret all our failures.

When doctors reverse their opinion of a medical practice it is usually because they adopted something that had a promising story, that they expected and hoped would work, but that was only supported by data that were modest, at best. Then, years later, when tested rigorously — in a well-designed randomized trial — some of these practices fail. The human body is beautifully complicated and our best guess as to what will work has led us astray in cases as diverse as vitamin supplementation and surgical interventions, specific therapies for high blood pressure and elevated cholesterol, and both conventional and alternative health care.

Medical reversals happen when accepted medical practices are overturned. They are not replaced by something better, but are shown — often surprisingly — to be no better (or worse) than either the previous standard or no intervention at all. Our research has shown that medical reversals are common — for instance, over the last decade, we found over 100 reversed practices. Reversals include estrogen replacement to postmenopausal woman, which was ultimately shown to be ineffective and dangerous; as well as injecting cement into the vertebrae of patients with fractures related to osteoporosis, which is no better than a placebo. The use of the supplement saw palmetto to improve prostate symptoms or echinacea to fight the cold were two other medical practices that were widely used, cost millions and later were found not to work. Recently, Vitamin D supplementation for healthy women to maintain bone health was added to this list.

The lesson for both doctors and patients is simple: When considering a medical therapy — a medical treatment, a surgical intervention or a diagnostic test — we should not get sidetracked by the story why it should work or even how much it costs. We should just consider whether it has proven itself in a clinical trial.

Dr. Vinay Prasad (vinayak.k.prasad@gmail.com) is an assistant professor of medicine at Oregon Health and Science University. Dr. Adam Cifu is a professor of medicine at the University of Chicago. They are authors of the forthcoming book "Ending Medical Reversal: Improving Outcomes, Saving Lives" (Johns Hopkins University Press, October 2015).

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