Where Is The Deception in Evidence-Based Medicine? — R.G.
I was first introduced to the concept of Evidence-Based Medicine (EBM) sometime in 2013 during one of my biomedical ethics lectures. On first blush I thought: how else would you proceed in medicine without evidence? How can you critique something so, well — obviously good?
It was only as I thought more and read more about the practice of EBM that I began to understand why many clinicians push back against it. But it still seems that the push back is either misplaced or merely trivially correct. W.W, in his post, also pushed back against EBM; which I think is unwarranted.
I’m going to also deploy the same definition W.W used in his post. Evidence-Based Medicine (EBM) can be defined as “the conscientious and judicious use of current best evidence in clinical care research in the management of individual patients”.
When I read this I think the argument is over. But we first need to get some intuition in place.
Medicine is about populations. Conceptually, medicine is not about individual treatment but rather a set of accepted treatments that generally yield positive results for a broad number of cases with similar variables. I understand why this is not intuitive but it is important to grasp. On the other side of the spectrum, suppose medicine was fundamentally individualistic — what would that look like? Since every person has a unique genomic structure then the most precise treatment for anyone would conceivably be unique for each person and not transferable to others. But of course we know that that is not how medicine is practiced. You do not go to the doctor with some sniffles and the first thing he does is sequence your genome.
There are patterns across people for how certain illnesses manifest. And similarly, there are patterns across people for how to treat illnesses. If doctors can not make assumptions based on stylised facts then their utility would be exceedingly limited. A doctor, in most cases, does not need to know your entire life history (or complete genomic structure) to get to a robust hypothesis. This is because medicine is about populations, i.e substantiating individual treatment based on generalized facts.
Evidence-Based Medicine (EMB) only formalizes what medicine already does. It is not an improvement or a regress. It is old wine in a new statistically significant bottle.
EBM emerged in the second half of the last century to combat a seemingly endemic problem: the variability of medical treatment decisions between doctors for similar problems was quite high. This is a serious problem that stems from the fact that medicine is a clinical practice and not a science in itself. That is, doctors (who are people too and not machines) have to condense all the possible worlds of treatment decisions based on the details they can ascertain from examination. Unfortunately, the solution to an illness is not inscribed on your cells.
But as fallible agents doctors can and do make mistakes. And unfortunately not every doctor is as talented as W.W. To reduce this problem, EBM aimed to reduce subjectivity and inject some kind of objectivity into treatment decision making.
W.W does agree with this point but he suggests something went awry along the way. We do not agree. I think the problem with EBM does not lie with EBM but with the doctors themselves who read EBM results.
The evidence part of Evidence-Based Medicine requires some reflection. As someone who spent (endured?) years studying epistemology I know that not all forms of evidence are equal. (You can even say some are more equal than others.) In clinical settings this is usually displayed as a Levels of Evidence hierarchy in pyramid form.
Opinions could be considered evidence but at best it is fragile evidence. W.W stated clearly that the core of his argument with his fellow doctor “concerned some word of mouth claims”. I would say that if you want to push back against EBM then you would need to have a stronger example than something based on fragile evidence. Fragile evidence is already accepted as near-useless under EBM conditions.
Next, W.W gave the example regarding studies on the use of aspirin for prevention of Atherosclerotic Cardiovascular Disease (ASCVD). The 2019 ACC/AHA Recommendations said there was insufficient evidence (meaning: no significant statistical evidence) to “comment on whether there may be select circumstances in which physicians might discuss prophylactic aspirin with adults <40 years of age or >70 years of age in the context of other known ASCVD risk factors”. W.W accuse these recommendations of being “vague” and not helpful.
In reality, it should be understood that studies can be done with an outcome that there is not sufficient evidence to reach a conclusion. That is often the case with sober, robust, nuanced studies. I understand why this can be unsatisfying. But the whole point of EBM is to aid the treatment decisions of clinicians and not to replace the judgement of clinicians.
The onus is still on the clinician to make the call he thinks is best. Moreover, I think there is still benefit to the above study. Given the above recommendation, tt would be irresponsible for a clinician to say to a patient something like “there is clear evidence that this will help you.” That would be false. He could however say “based on my knowledge of the risk involved, your specific case, and the potential outcomes I will still recommend the aspirin for you.” This is an honest treatment decision borne from the recommendations.
It is important to keep in mind that because of misplaced incentives bad studies can be published. In academia (people who want medical faculty tenured positions need to publish or perish), industry (corporate needs require pharma companies to sometimes skew and p-hack data for their preferred outcomes), social brownie points (some clinicians without much statistical training want to publish EBM papers anyway), and bad academic journals (since people want to publish businesses will do it for them no matter the laziness of the analysis).
This is a problem all over and does not actually say much as a critique of EBM qua EBM.
What I can’t shake is that it often seems that some clinicians may want to be absolved from making decisions. Making what is literally life and death decisions is not something to easily get used to. And I get that this can be anxiety inducing. In this context EBM is an obvious idol to worship. For young doctors this could be even more alluring. In the example from W.W with his fellow doctor who wanted to believe the ibuprofen tale, s/he may be just looking for an “out”. The deception does not lie with EBM. Instead, the deception lies with the doctor who wrongfully thinks EBM can be an “out”.
In reflecting on what I said above my main push back against W.W on this topic is: Don’t force EBM to do what it was not meant to do. EBM is an aid and not a crutch.
To wrap up, I think EBM is fundamentally an unveiling of medicine. EBM only formalizes what medicine already does. Your discomfort towards EBM may be just a discomfort to the methodologies of medicine more broadly. At the margin do we actually know so little concrete and robust facts? As a doctor do I really have to do this much guess work? Do I really have to take on the responsibility of being wrong?
Perhaps.
