Misconceptions about Evidence-Based Medicine

Evidence-Based Medicine: Common Misconceptions, Barriers, and Practical Solutions – JAY SIWEK, MD, Georgetown University Medical Center, Washington – Sep 2018

More than 25 years have passed since the term evidence-based medicine (EBM) was introduced into the medical literature. Its original definition has been expanded to include not only the quality of the evidence, but also the two key players applying the available evidence—namely the clinician and patient.

A current working definition is: the integration of the best available evidence with clinical expertise and the individual patient’s values, preferences, and unique circumstances.

EBM is not dogmatic, “cookbook ” medicine.

Oh really? But that’s exactly how it’s being used.

Lazy doctors can look at the guidelines and just do exactly what it tells them to, not much better than a computer, and still make their hospital managers happy.

But it’s the doctor’s judgment and experience that provides the real value, and that’s getting lost or overridden by all the standardization being introduced into healthcare.

Instead, it relies on the expertise of a conscientious clinician in partnership with the patient. The clinician must navigate a sea of information and decide how best to apply it to the individual patient.

And the patient—increasingly informed about all sorts of evidence—has the right and even responsibility to participate in shared decision making, especially for high-stakes decisions, values-driven decisions, and decisions in which there are several similarly effective options.

Sometimes, patients knowingly decide against what the clinician believes is “best” and instead choose what is “best for them,” based on how they value specific benefits and harms.

Many clinicians mistakenly believe that applying some evidence is practicing EBM. That depends, however.

But with opioid prescribing mostly only defective evidence is available. And it’s not even realized how defective it is, like so many studies about opioid doses that highlight their disadvantages without ever taking into account that they decrease patient pain levels,

What counts is basing clinical decisions on the best available evidence, not just any evidence.

And yet, the above-mentioned seriously flawed opioid studies are often the only evidence that’s used for prescribing.

We have all had the experience of seeing one randomized clinical trial contradicted by another.

This is especially true when trials measure surrogate outcomes such as blood pressure or blood glucose level rather than patient-oriented outcomes, when study populations and interventions differ in important ways, or when trials have different levels of intentional or unintentional bias.

EBM requires the daunting task of evaluating all relevant evidence—something that clinicians in practice cannot be expected to do. That is why it is important to identify and use high-quality sources of preappraised evidence, for which a team of experts has done the heavy lifting, sorting through hundreds or even thousands of studies to produce systematic reviews and meta-analyses that synthesize the available evidence.

Premier examples are the Cochrane Collaboration (https://www.cochrane.org/evidence) and the U.S. Preventive Services Task Force (https://www.uspreventiveservicestaskforce.org/).

Then, look for sites that craft clinical guidance using these sources, such as DynaMed (http://www.dynamed.com; subscription required) and Essential Evidence Plus (http://www.essentialevidenceplus.com/; subscription required).

As noted earlier, beware of the pitfall of relying on surrogate outcomes, such as blood glucose measurements or other physiologic parameters.

Many researchers are forgetting that opioid milligrams are only a surrogate outcome, while patient pain levels and the reason for which those opioids were taken are completely ignored. See Opioids Blamed for Side-Effects of Chronic Pain.

Instead, try to find patient-oriented evidence that shows improvements in morbidity, mortality, and quality of life.

The above is absolutely critical to medical practice, but is often ignored because researchers can find much more easily measurable surrogate outcomes, like opioid dose,s whereas human outcomes, like pain level or functionality or quality of life, are much more difficult to measure and much more subject to bias and confounding.

The Strength of Recommendation Taxonomy (SORT) evidence rating system used by American Family Physician (AFP) and other family medicine journals assigns higher grades to the latter. At AFP, we feature a collection of POEMs (patient-oriented evidence that matters; https://www.aafp.org/afp/poems) and each year publish the top 20 POEMs of the preceding year (https://www.aafp.org/journals/afp/authors/ebm-toolkit/resources/top-poems.html).

Finally, we have an EBM Toolkit to aid in putting best evidence into practice (https://www.aafp.org/journals/afp/authors/ebm-toolkit.html).

Author: Dr. Siwek is Editor Emeritus for AFP.

3 thoughts on “Misconceptions about Evidence-Based Medicine

  1. peter jasz

    Dr. Siwek: Brilliant !

    Unfortunately, I suspect there are very few as sensible (see through the fog/confusion -or even care) and passionate as yourself.

    peter jasz

    Liked by 1 person


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