Good Medical Decision-Making: Much More than Applying Evidence

By Robert L. Moore, MD, MPH, MBA, Chief Medical Officer

“Medicine is best described not as a science, but as a form of flexible practical reasoning that often uses science.”

Adam Rodman, MD

How do the best clinicians apply their knowledge?

Last year, this monthly newsletter reviewed the propensity for mental shortcuts, biases and prior experiences that lead to poor medical decision-making, and discussed options for minimizing the degree that these cognitive traps affect our clinical decisions. Think of this as the cognitive psychology of medical decision-making.

When mental shortcuts are minimized, and reasoning is applied, we might, at first blush, think that the best reasoning limits itself to “Evidence Based Medicine” where high quality, prospective, placebo-controlled, double blind, allocation concealed studies are consistently applied in making medical decisions. In reality, several sources of knowledge (sometimes conflicting with each other) are brought to bear. The study of the nature of knowledge is also known as epistemology, a branch of philosophy. Within the medical realm, this is known as medical epistemology, a branch of the study of the philosophy of medicine.

In a grand rounds at Beth Israel Hospital in October, 2019, clinical professor Adam Rodman, MD defines a historical framework of medical epistemologies that clinicians use to decide on what treatments to offer patients:

  1. Observation – This involves obtaining a careful and complete history and physical examination, with review of lab work to categorize the disease or diseases that a patient has, and recalling how similar patients/disease categories that the clinician has directly observed or heard/read about have responded to treatments given. The earliest example of this is the 4,000-year-old Edwin Smith papyrus, in which an ancient Egyptian healer carefully described a series of 48 surgical cases and their treatments.
  2. Theory – Pre-scientific theories, such as ancient Greek humoral theory of disease dominated medical practice until the mid-nineteenth century, when they were replaced by scientific theoretical frameworks, such as physiology, immunology, biochemistry. These frameworks are then used to interpret observations (such as a rising creatinine in a patient receiving a diuretic), and make judgements based on this understanding.
  3. Experimentation/Clinical Trials – While there are scattered examples of medical experimentation before 1900, it was not very commonly used. It is primarily a twentieth-century framework, and led to the Evidence-Based Medicine movement, starting in the late 1980s. It includes applying a hierarchy of different types of medical trials and studies, with expert opinion at the bottom of the pyramid and meta-analysis reviews at the top. This pillar of understanding has crumbled to be replaced with the current standard: grading of available evidence, which takes many other factors into account.
  4. “Population Medicine”/Epidemiology/Biostatistics – This began in the early 1800s, in Paris and was first called the “Numerical Method.” This involves collecting data on numbers of patients and analyzing this data statistically for insights that can then be used to improve clinical decision making for the individual patient being cared for. The most modern applications of this are decision rules (for example for osteoporosis screening or genetic testing), “big data” analyses, and augmented intelligence medical applications.

Rodman contends that whenever clinicians make treatment decisions on individual patients, we use some or all of these frameworks, even on the same patient, in the same day. The frameworks often might lead to conflicting treatment options which need to be sorted out rationally. Importantly, the third framework is the preferred framework for Evidence-Based-Medicine purists, but real-life excellent clinicians seamlessly integrate EBM with the other 3 frameworks. We need not feel guilty or inferior when we use these other frameworks; they have a vital role in the decision making of all excellent clinicians.

In the end, to the extent medicine uses science, it is in the application of science to deciding on individualized treatment of patients that matters.

The medical ethicist Jose Alberto Mainetti stated it best in his research, Embodiment, Pathology, and Diagnosis: “Diagnosis is not knowledge for knowledge’s sake. It is knowledge for the sake of action. Medicine exists to cure, to care, to intervene, or in limiting cases to know when not to intervene. Medicine is not a contemplative science.”

Knowing the noble history of these four epistemologies can help us balance their use thoughtfully, both in our continuing educational activities to better master them and in applying them to make therapeutic decisions that best serve our patients.

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