The Art of Evidence-Based Medicine

Evidence-based  medicine now routinely defines the standard of care for many conditions. This approach mandates that new information, gleaned from randomized controlled trials and consolidated into clinical practice guidelines, can and must be used to improve the quality of care that patients receive. However, there is a critical misunderstanding of what information randomized trials provide to us and how health care providers should respond to the important information that these trials contain.

Although, in theory, evidence-based medicine does not assume that when faced with two treatment options, patients should always receive the treatment that was more effective in randomized controlled trials, this tends to be what happens in practice. Ultimately, because of heterogeneity in how patients respond to treatment, it is possible, and likely, that physicians who are informed about the evidence may still appropriately offer some patients a treatment that many would consider to be inferior on the basis of clinical trial data alone.

This simple point has several important, but unfamiliar, implications for how we measure the quality of health care that patients receive and how narrowly we should interpret the recommendations of evidence-based medicine. It is possible that informed physicians who combine their own clinical experience with up-to-date scientific evidence may have better outcomes than physicians who unanimously choose treatments shown to be effective, on average, in clinical trials.

Clinical pathways, protocols, electronic physician order sets and checklists are also often designed to increase adherence to clinical guidelines and improve performance on quality metrics. While they may provide guidance to some physicians, others may be nudged to provide treatments that, in the end, are the wrong treatments for their patients.

Ultimately, the successful application of evidence-based medicine is an art that requires first and foremost an awareness of the evidence, and also an ability to determine how well the evidence applies to any given patient.

None of this is to say that evidence-based medicine is not helpful. It clearly is. But the optimal application of evidence is as important as awareness of that evidence, and physicians must be artists, using their judgment to determine which evidence applies best and which treatments will most likely benefit individual patients.

(Christopher Worsham is a critical care physician at Massachusetts General Hospital and Harvard Medical School. Anupam B. Jena is an associate professor of health care policy at Harvard Medical School and an internist at Massachusetts General Hospital.)