What evidence guides clinical decisions?

Whenever possible medical decisions should be guided by scientific evidence. When I was a medical student in the early 1970s we had a visiting professor David Sackett from McMaster University in Canada. Dr. Sackett is widely regarded as the father of evidence based medicine (EBM).His definition of EBM is still used today: “the conscientious, explicit and judicious use of the current best evidence in making decisions about the care of the individual patient” (Sackett D, 1996 https://pubmed.ncbi.nlm.nih.gov/9190027/). Dr. Sackett made a major impression on me about the need to be flexible in the selection of evidence because most clinical problems will not be answered by randomized controlled trials (RCTs).

My favorite course in medical school was The Pathophysiology of Disease. This course put together all the basic science knowledge with pathology (the study of disease) leading to an understanding of human biology and disease development. This scientific understanding of disease helps guide clinical treatment and progress in medicine. Watching this knowledge evolve over time is the scientific basis of medicine.

Advocates of EBM today are locked into what comes from RCTs. RCTs are expensive, focus on a single variable and require large populations. Most such trials today that address topics relevant to clinic practice are funded by the pharmaceutical industry, and hence foster the use of drugs. The knowledge that comes from RCTs is important but is not helpful for most clinical decisions. Worse, RCTs with their single variable focus may get in the way of good clinical decisions, such as giving good dietary advice. For example, RCTs suggest that a low fat diet is as good as a low carbohydrate diet, information they goes against the current understanding of what causes overweight and obesity, excess carbohydrates.

Most chronic diseases today, such as hypertension, overweight and obesity, prediabetes and diabetes, and elevated cholesterol are caused by lifestyle factors such as the Western diet and a sedentary lifestyle. In Functional Medicine, these lifestyle factors are addressed to reverse the diseases. Often the medications used to treat chronic diseases can be stopped when the patient adopts a healthy diet and lifestyle. This type of clinical practice consists of true healing of the patient and is very satisfying.

I am convinced that primary care and much of medicine today are in an “evidence desert”. The limitations of EBM have allowed most clinicians to be overly conservative in their treatments, resulting in patients taking medications they could avoid. The scientific foundation of Functional Medicine is a better understanding of human biology and the impact of diet and lifestyle factors. The clinical research is empirical with small studies that are practical given the funding limitations. When empirical data and small studies match the latest understanding of our human biology, the evidence should be considered sound.While we stay humble and open to new information changing clinical practice, we should use the best clinical evidence today from a variety of sources to guide our practice.

Joseph E. Scherger, M.D., M.P.H., is a family physician at Eisenhower Health in La Quinta, California, and is a member of the Medical Economics® editorial advisory board. He is also a core faculty member with the Eisenhower Health Family Medicine Residency Program. Dr. Scherger is clinical professor of family medicine at the Keck School of Medicine at the University of Southern California (USC), and is a leader in transforming office practice.