Evidence based medicine (EBM) done right: Deming, not Taylor

Evidence Based Medicine (EBM) is a relatively recent but very popular development with great potential for both good and ill.

Effectiveness and Efficiency: Random Reflections on Health Services (1972)  by the Scottish epidemiologist Archie Cochrane (namesake of the Cochrane Collaboration) first made the case for applying the best evidence available from scientifically valid studies to clinical decision making.

The core methodologies for assessing and applying evidence in clinical decision making were first set forth by Guyatt and Hackett at McMaster University. (See footnote.) Guyatt coined the term evidence-based about 1990 and the term ‘evidence based medicine first appears in Guyatt’s 1992 paper from the McMaster Evidence-Based Medicine Working Group (November 1992). "Evidence-based medicine. A new approach to teaching the practice of medicine". JAMA 268 (17): 2420–5.

Since then, EBM has become one of the touchstones of modern medicine. Because it serves equally well to illuminate good practices or enforce mediocrity, and has too frequently and successfully been co-opted by third parties and administrators to create an illusion of coherence and consistency where variability is king, it is both beloved and detested. (To say nothing of how it is misunderstood and misapplied by the media.)

Intermountain HealthCare stands out as an organization that has been successful at applying EBM for the benefit of their patients, with enthusiastic engagement among their providers. A quote from an interview (do read the whole thing - it is an excellent discussion) with Bob Wachter from Intermountain  makes a key point about EBM, one that underlies their success, and one that is often lost or ignored. Discussing their early start on EBM, he notes they asked:

“...what would happen if we establish an evidence-based best practice protocol, fully understanding that you really can't write a protocol that perfectly fits any patient.

Now I would argue that this is the core of that culture. All clinicians who practice for any time at all quickly understand that every patient is different. And this idea of a cookbook, a straitjacket, it just doesn't fit reality. Well, we thought that was fundamentally true. You can actually make the case in a fairly convincing way that all patients are different. So we established an evidence-based best practice protocol fully realizing that you could not write a protocol that perfectly fit any patient in the vast majority of circumstances. There are a few narrow circumstances where you can. To our physicians I say, ladies and gentlemen, it's not just that we allow or even encourage that you adjust this to the needs of your individual patients, we demand it.”

EBM is neither a recipe nor an algorithm published in the most recent version of Medicine for Dummies. It is not the answer to the question: ‘What is best for this patient?” It is certainly not an excuse for not thinking, or for not creating an individual diagnostic or therapeutic plan for each individual patient. It is merely a summary of collected and validated information about a mythical ‘standardized’ patient constructed from aggregated data from a population of individual patients. It is no more a real patient than a Lego model is a real building suitable for habitation.

It is none of these things. Yet it is powerful and informative when used correctly, as a starting point from which one derives an individualized plan. It does not determine the answer, it informs the answer.



Footnote: The concept of testing medical interventions for efficacy has existed since the time of Avicenna's "The Canon of Medicine" in the 11th century.

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