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Dr. Steven Hatch investigates the ‘spectrum of certainty’

Marianne Karmel

According to a 2015 Gallup poll, nurses and doctors are America’s most trusted professionals. This may come as a surprise to many nurses and doctors. Patients today are more likely than ever to challenge medical advice. Years ago, doctors prescribed and, for the most part, patients complied. Today such issues as vaccine safety, the utility of cancer screening tests, and the risks and benefits of taking various medications are common topics of discussion — and debate — between patients and their doctors.

Dr. Steven Hatch, a specialist in infectious diseases at the University of Massachusetts Medical School, believes that, ironically, medical professionals would face less skepticism if they were more open about their limitations. In his new book, “Snowball in a Blizzard: A Physician’s Notes on Uncertainty in Medicine,” he explores several questions for which definitive answers are not available, such as: Who should have a mammogram? What’s an optimal blood pressure reading? When should a statin drug be started?


In a telephone interview, Hatch said that he was first inspired to write the book in 2009 when the US Preventive Services Task Force issued new guidelines regarding mammography: Women over 50 may not need screening mammograms every year and women under 50 may not need them at all. The guidelines caused outrage among women who suspected their health care was being rationed but Hatch, who studied the primary data on which the guidelines were based, drew his own conclusion: Mammography is not as powerful a cancer screening tool as was once thought. Its utility, like that of prostate specific antigen to detect prostate cancer and statins to prevent heart disease, isn’t absolutely certain but falls somewhere on what Hatch calls the “spectrum of certainty.”

Hatch believes that doctors are trained from medical school on to believe “that there always must be a right answer.” This belief can have negative effects on patients. “When you stumble upon a patient where you don’t know what’s going on, it is very hard for certain physicians not to be frustrated with the lack of an answer — and they take it out on their patients,” Hatch said. Patients whose symptoms confound their doctors sometimes receive less attentive care than those with more easily diagnosed conditions.


One such group of patients, to whom Hatch devotes a chapter in his book, are those with chronic fatigue syndrome. Many believe their symptoms are caused by persistent Lyme disease and request months of antibiotic therapy despite lack of firm evidence that chronic Lyme exists or that such therapy is effective. Hatch is sympathetic to these patients as well as with parents convinced that vaccines caused their children’s autism despite overwhelming evidence to the contrary. “Both autism and chronic fatigue are problems for which Western medicine hasn’t cracked the code,” Hatch said. Patients, like doctors, believe there must be an answer, even if they disagree on what the answer is.

The media, too, contribute to a culture of certainty around medical issues. Hatch describes several instances, including one involving TV journalist Katie Couric’s discredited report on dangers of the HPV vaccine, in which the press misrepresented data for the sake of a dramatic story. As a doctor who has made several trips to West Africa to treat patients with Ebola, Hatch is sensitive to lack of nuance in coverage of medical issues. Regarding Ebola and, now, Zika, Hatch observed, “The media loves a scary virus.”


Despite his focus on uncertainty in medicine, Hatch still believes that medicine is a science. “We’re a practical science,” he said. “We’re more like engineers than physicists, because we’re concerned with making changes in the real world. We go with what works at the moment, rather than seeking some pure medical ‘theory of everything.’ ”

He thinks patients would be more sympathetic to this admission than doctors might imagine.