EBM suggests that doctors should avoid prescribing treatments that do not have sufficient or strong evidence in their favor. Decisions made backed only by expert opinions and supported by plausible pathophysiological explanations, although not yet sufficiently proven by high-level clinical studies, are not recommended by EBM in ordinary situations. However, in a serious epidemiological emergency, there is no time for such studies to be available. Under such circumstances, could not (or even should not) doctors agree to provide recommendations to their patients guided by studies or opinions based on unsatisfactory or weak evidence?
It seems reasonable that in a "serious emergency" we can apply a rationale less stringent, that is, less precautionary. But what is meant by a "serious emergency"? Of course, the Covid-19 pandemic is serious, nevertheless it is not serious in the sense of putting humanity at risk. If we were facing a highly serious emergency that could put at risk the existence of humanity, it could be reasonable to apply a catastrophic principle (see Possner, or Sunstein about that).But this is not the case. In fact, the clinical predicaments we are facing in ICUs are ordinary clinical difficulties, although embedded in a context of a serious epidemiological crisis. We can interpret the view behind EBM rationales as the bioethical principle of clinical equipoise: it's wrong to submit patients to known possible harms (possible side-effects) in circumstances of weak knowledge of possible benefits, specially if the possible benefits are not significantly high. Consider the case of the suggested pharmacological treatments for Covid-19. The treatments (hydroxychloroquine, for example) do not promise the cure of the disease, but only a possible reduction in the severity of the disease. At the moment, the evidence are of low quality and the recommendations are weak. So, what the evidence signals is that or the treatments do not work, or they work but with a slight effect. It is nevertheless known that the treatment may cause side effects.To the extent that we do not know how reality behaves (if the treatments work or not), the patient may be in one of two possible branches: either in a branch of reality in which the proposed treatment achieves a discrete beneficial effect, or in a branch of reality in which that it does not produce any benefit at all. At the same time, we know that in both branches of reality, treatment can cause side effects (and in the case of hydroxychloroquine we already know that in the most severe cases it increases the risk of serious side effects, including death). Note that if the patient does not receive the treatment he will not be subject to these risks of harm. Then, it is clear that there is no clinical equipoise. Unless the anticipated benefit is significant, it is unreasonable to offer a treatment that is known to increase the risk of harm, especially in cases where, due to the clinical severity (ICU patients), the patient could consider (considering that he is in a circumstance of ignorance) that it would be rational (Maximin) to submit to already known risks to obtain a large benefit but of unknown probability. The problem is that we know that the possible benefit is not large enough (in the case of the proposed treatments) and the evidence about its probability is unfortunately poor.
Dear Vijay, I disagree with you for actually we have evidence, but almost all of them are WEAK. In the case of hydroxichloroquine, we actually have at least one RCT (with some frailties, unfortunately), that did not recommend the treatment (there weren't significant differences between the arms of the study, so the null hypothesis wasn't rejected). Nevertheless, we have studies showing that in the serious cases of Covid-19 this treatment is more harmful than beneficial. We don't have any strong evidence that this treatment prevent the escalation of disease into the most serious outcomes (even though we have some weak evidence that this could be true). Given that, we can of course apply the principles of EBM. For example, using the GRADE systems, the most reasonable conclusion is that since we have weak evidence for those treatments and strong evidence for some serious side-effects, the recommendation is against a public police that could support the use of, for instance, hydroxichloroquine in Covid-19. Patients, nevertheless, could demand this choice and I think that clinicians can consider that with cautions in a shared-decision making process. The view that EBM does not apply in circumstances of ignorance is, nevertheless, an alternative view about the rationales of clinical practice under poor evidence. Even though my point-the-view is different (I think as argued above that EBM can be applied successfully), I think you have a point that deserve to be explored. Maybe there are circumstances of poor knowledge in which we could and should use a Bayesian framework that accepts some risks and propose bets in the better alternatives for the moment. It would be like a Pascalian wager. This maybe applies to the so-called compassionate uses of medications. The problem is if this also applies to the so-called "early treatments" with antivirals. I don't think so.
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