Snowball in a Blizzard: A Physician’s Notes on Uncertainty in Medicine, by Steven Hatch (New York: Basic Books, 2016)
When he started this book, Steven Hatch intended to write about issues with which he was struggling in his professional life as assistant professor of medicine at the University of Massachusetts Medical School. The focus would have been on “methodological aspects of human-subjects research, mainly the difficulties of study design and the subtleties of statistical interpretation” (p. 241).
Tepid responses from literary agents led him to realize that “more was to be gained by telling stories about the consequences of these issues, and that I could occasionally sprinkle the text with brief explanations of the more essential methodological points.” How should women decide when to have mammograms and how much confidence should they have in the results of these tests? How reliable are PSA scores in making decisions about possible prostate cancer? Why are guidelines for blood pressure levels changing, especially for older adults?
The first half of the book consists of Hatch’s narratives about the above illnesses and others, including infectious diseases, his own field of specialization. The mix of case study narration and description of how scientists and physicians conduct studies and reach conclusions provides a strong story line so that general readers can stay with his analysis and understand his interpretations.
Halfway through (p. 153), Hatch summarizes the book to this point. Studies discussed in previous chapters leave questions dealing with uncertainty about the values of a drug: “First, what will be the yardstick by which we will measure a drug’s value? … Second, how big will any potential observed benefit need to be before we consider it a success? . . . Third, what are the potential harms of the treatment?” After listing and briefly explaining these questions, Hatch states what could be considered the thesis of the book.
“Because the answers to these questions differ for each treatment, and the fact that the answers tend to fall onto a continuum rather than cozy themselves into a tidy binary yes and no category, both doctors and patients alike need to carefully consider the data before ‘knowing’ that a drug is right for them” (p. 153).
Hatch then begins a fuller discussion of the processes by which physicians and researchers reach their conclusions. The chapter title and epigram suggest the tone of what follows: “The Correlation/Causation Problem, or Why Dark Chocolate May Not Lower Your Risk of Heart Failure: The science was accurate, but it was extrapolated beyond imagination.”
He also gives a concise description of the kind of study that has been described and affirmed throughout the book and makes this assertion: “Nevertheless, the power of the double-blind, randomized, placebo-controlled trial lies in its ability to ask [the above questions] in an organized and systematic way. We can say this drug saves this many lives (great!) but comes at the cost of these side effects, of which these particular effects are truly dangerous (not great). They do not settle questions, but they give us a framework by which we can ponder uncertainty and allow us to decide where we can place a drug’s value on the spectrum (154).”
The ideas presented in this book lead to a specific kind of relationship between medical providers and patients and families. Instead of issuing decisions about treatment, doctors exercise humility, explaining the basis for their proposals for treatment and acknowledging the limitations of their knowledge and certainty. Patients and families need to be active participants in the discussion, asking questions and responding to the guidelines that physicians present.
This relationship is illustrated in a pattern of consultation that is developing in intensive care units. Families are encouraged to be present at the bedside when the medical team makes its daily rounds to evaluate the patient and the care that is being given. In this way, the conversational, collaborative nature of the doctor-patient relationship is manifested.
Hatch frequently describes the role of the media in describing medical matters and developing public opinion. Much of his commentary is negative and he supports the importance of good coverage that reports carefully on studies, recommendations, and guidelines.
Despite Hatch’s emphasis upon uncertainty, humility, and collaboration, he does make one unqualified assertion at several points throughout the book: “Exercise more. Eat less. Don’t smoke. Everything else is commentary” (p. 225). Hatch also writes that there is one aspect of medicine where the benefits are so great and the risks so minimal that it is on the far left of the “spectrum of certainty.” That procedure is vaccination, which has to be considered “the single greatest triumph of modern medicine” (222).
My wife died of metastatic breast cancer, and I deal with prostate and blood pressure issues. During the past decade, we had many conversations with a wide range of doctors and consultants. Our experience has been increasingly along lines that are consistent with Hatch’s recommendations. We would have been helped if we had been able to read a book like Snowball in a Blizzard.
This book is a key to good health!