When Doctors Refuse to Believe Evidence

Paul Offit’s new book covers the evidence for many surgeries, medications, and screening tests that have been proven ineffective and harmful yet are still being used by doctors who refuse to follow the science.

Science-based medicine is all about testing medical ideas against reality. If there is abundant evidence from well-designed controlled clinical trials that a treatment is safe and effective, science-based doctors can feel justified in using it. If the evidence shows that the treatment doesn’t work and does harm rather than good, they abandon it. At least that’s what they logically should do. But all too often, that’s not what actually happens. Sometimes doctors refuse to believe the evidence and persist in doing things that don’t work and cause harm, including popular surgeries, medications, and screening tests. You might think that’s a rare occurrence; but it’s actually very common, as Paul Offit shows in his new book Overkill: When Modern Medicine Goes Too Far.

He covers 19 common beliefs that aren’t true, that have been repeatedly disproved by good scientific studies. He explains how and why the false beliefs arose and why they have persisted, describes the many studies that have produced good evidence that the beliefs are false, explains why some studies have produced different results, explains the science behind why a treatment works or doesn’t work, and ends by offering suggestions to overcome typical arguments for the persistence of false beliefs and suggestions about how to improve medical practice.

The false beliefs refuted

Clarification added 11/17: Some readers found this confusing.  No, it’s not a list of false beliefs; it’s a list of Offit’s refutations.

  1. Fever doesn’t need to be treated. (More about this later, and you can also review Clay’s post on the topic.)
  2. Finishing a course of antibiotics is often unnecessary. (Actually, the length of a course of treatment is arbitrary, not evidence-based; and it makes more sense to stop the antibiotics when the symptoms have resolved. And it may help prevent drug resistance. Discussed by Scott!)
  3. Antibiotic drops don’t treat pinkeye.
  4. Vitamin D supplements are rarely necessary, and they don’t do most of the things people think they do. (See Scott’s post)
  5. Supplemental antioxidants don’t lower the risk of cancer and heart disease; they increase it . (Another post by Scott)
  6. Testosterone for “Low T” is dangerous and unnecessary. (See David’s post)
  7. Baby aspirin doesn’t prevent first strokes or heart attacks and it can cause bleeding complications. It does work to prevent strokes or heart attacks in patients who have already had one. (Scott again)
  8. If allergenic foods are introduced to infants at an early age, they will be less likely to develop allergies. (Discussed by Scott)
  9. Reflux medicines for fussy babies should be avoided. Babies spit up; that’s normal. The drugs don’t reduce regurgitation or clinical symptoms, yet they are prescribed for one out of every ten babies in the US. (Discussed by Clay)
  10. Sunscreens offer false security; users spend more time in the sun and get more skin cancers.
  11. Prostate cancer screening programs do more harm than good. (Discussed by David)
  12. Thyroid cancer screening programs don’t save lives. (David again)
  13. Breast cancer screening programs aren’t exactly as advertised. For every 1000 women screened, 7 lives will be saved but 19 will be diagnosed with a cancer that never would have killed them, and of those 19, 99% will have surgery, 70% radiation, 70% hormone therapy, and 25% chemotherapy, all without benefit. (David)
  14. Heart stents don’t prolong lives.
  15. Surgery for knee arthritis is unnecessary, especially arthroscopic procedures. Even total knee replacement is problematic: 85% of patients had less pain but so did 65% of the nonsurgical comparison group.
  16. Mercury dental fillings should not be removed. They’re not causing health problems, and removal increasesmercury exposure.
  17. Vitamin C doesn’t treat or prevent colds.
  18. The standard advice to treat sprains with RICE (rest, ice, compression, and elevation) may do more harm than good: all four reduce blood flow and retard healing, as do anti-inflammatory drugs.
  19. Teething doesn’t cause fever. (Clay)

For some of these items, you will say “I knew that.” Others may surprise you or strike you as wrong; but strong supporting evidence is provided in the book. We have covered several of these issues on SBM. You may not be ready to give up long-standing beliefs and practices. If you question some things on the list, I urge you to read the book and try to consider without bias the evidence Offit has marshalled.

The book has persuaded me to change my mind about some things. I had read arguments against treating fevers before, but I always rationalized that lowering body temperature wouldn’t make that much difference and that treating fever makes patients feel better. Offit points out that fever is a natural response that evolved in all animal species because it was beneficial; he says “We’re not supposed to feel better.” Fever is a signal that we should rest and let our body fight the infection at a higher temperature that allows every aspect of our immune system to work better. There is reassuring evidence that letting a fever from infection run its course will not “fry the brain” or kill the patient like heatstroke or malignant hyperthermia can, and that giving Tylenol before vaccination will not prevent a febrile seizure. So I have resolved that the next time I run a fever I will just go to bed and tough it out. It’s a good excuse for a mini-vacation. And if I sprain my ankle, I will not put ice on it, and I will try to tolerate mild activity.


If the evidence is so clear, why doesn’t everyone accept it? Offit gives several possible reasons.

  • Ignorance: no one can keep up with all the published studies, and some of the studies are poorly designed and report misleading results.
  • Fee for service: there are financial incentives for doing useless procedures. Solution: salaries that don’t depend on the number of procedures performed.
  • Patient satisfaction: patients want doctors to do something and are more satisfied when they get surgery or a prescription; they don’t have the knowledge to know what’s best for them and they have to depend on the expert (the doctor) for guidance.
  • Inertia: doctors want to continue doing what they have always done and what they have been taught to do. Their personal experience (which we know is not a reliable guide) has convinced them that it works, and it is painful for them to admit that they have actually been harming patients all those years.
  • Medical marketing: health advertising is a multibillion dollar industry that is poorly regulated. The U.S. and New Zealand are the only two countries that allow direct-to-consumer advertising for pharmaceuticals.
  • Fear of lawsuits: A jury awarded $986,000 to an alleged psychic who believed the MRI ordered by her neurologist had destroyed her psychic powers. Doctors may be sued for neglect if they refuse to take actions that other doctors take. Offit’s solution: eliminate jury trials; let a panel of medical experts decide if malpractice has occurred.

The take-home message: Trust science

This is an important book that is well written, accessible to laymen, and provides extensive evidence (51 pages of notes and references). Medicine would be healthier if all doctors and patients would read this book and follow the science.

This article was originally published in the Science-Based Medicine Blog.

Dr. Hall is a contributing editor to both Skeptic magazine and the Skeptical Inquirer. She is a weekly contributor to the Science-Based Medicine Blog and is one of its editors. She has also contributed to Quackwatch and to a number of other respected journals and publications. She is the author of Women Aren’t Supposed to Fly: The Memoirs of a Female Flight Surgeon and co-author of the textbook, Consumer Health: A Guide to Intelligent Decisions.

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