MD, PhD, FMedSci, FSB, FRCP, FRCPEd

EBM

I have often asked myself whether it is right/necessary to scientifically test things which are entirely implausible. Should we, for instance test the effectiveness of treatments which have a very low prior probability of generating a positive effect such as paranormal healing, homeopathy or Bach flower remedies? If you believe in the principles of evidence-based medicine you might focus on the clinical evidence and see biological plausibility as secondary. If you are a basic scientist, you are likely to do the reverse.

A recent article addressed this issue. The author points out that evaluating the absurd is absurd. Specifically, he noted that the empirical evaluation of a therapy would normally assume a plausible rationale regarding the mechanism of action. However, examination of the historical background and underlying principles for reflexology, iridology, acupuncture, auricular acupuncture, and some herbal medicines, reveals a rationale founded on the principle of analogical correspondences, which is a common basis for magical thinking and pseudoscientific beliefs such as astrology and chiromancy. Where this is the case, it is suggested that subjecting these therapies to empirical evaluation may be tantamount to evaluating the absurd.

This makes a lot of sense – but is it really entirely true? Are there no legitimate reasons at all for testing alternative treatments that lack biological plausibility? Ten or twenty years ago, I would have disagreed with the notion that plausibility is an essential prerequisite for scientific testing; today, I have changed my mind a little, but not as much as to agree completely with the assumption. In other words, I still see more than one good reason why evaluating the absurd might be reasonable or even advisable.

  1. Using plausibility as the only arbiter of scientific ‘evaluability’, assumes that we understand everything about plausibility there is to know. Yet it might just be possible that we mis-categorise something as implausible simply because we are not yet fully aware of all the facts.
  2. Declaring something as plausible and another thing as implausible are not hard and fast verdicts but judgements which, at least to some degree, are subjective. Sceptics find the axioms of homeopathy utterly implausible, for instance – but ask a homeopath, and you will hear all sorts of explanations which, at least to them, sound plausible.
  3. If an implausible alternative treatment is in wide-spread use, we arguably have a responsibility to test it scientifically in order to demonstrate the truth about it (to those proponents of that therapy who are willing to accept that rigorous science can find the truth). If we fail to do this, it will be the enthusiasts of that therapy who conduct less than rigorous science and produce false positive results. In turn, this will give the impression that the treatment is effective and mislead consumers, politicians, journalists etc. Seen from this perspective, it might even be unethical to not do the science.

So, I am in two minds about this (which might be a reflection of the fact that, during different periods of my life, I have been a clinician, a basic scientist and a clinical researcher). I realise that plausibility and prior probability are important – much more so than I appreciated years ago. But I think they should not be the only criteria. The clinical evidence should not be pushed aside completely.

I’d be interested to learn your views on this tricky issue.

As I write these words, I am travelling back from a medical conference. The organisers had invited me to give a lecture which I concluded saying: “anyone in medicine not believing in evidence-based health care is in the wrong business”. This statement was meant to stimulate the discussion and provoke the audience who were perhaps just a little on the side of those who are not all that taken by science.

I may well have been right, because, in the coffee break, several doctors disputed my point; to paraphrase their arguments: “You don’t believe in the value of experience, you think that science is the way to know everything. But you are wrong! Philosophers and other people, who are a lot cleverer than you, tell us that science is not the way to real knowledge; and in some forms of medicine we have a wealth of experience which we cannot ignore. This is at least as important as scientific knowledge. Take TCM, for instance, thousands of years of tradition must mean something; in fact it tells us more than science will ever be able to. Qi-energy, for instance, is a concept based on experience, and science is useless at verifying it.”

I disagreed, of course. But I am afraid that I did not convince my colleagues. The appeal to tradition is amazingly powerful, so much so that even well-seasoned physicians fall for it. Yet it nevertheless is a fallacy, I am sure.

So what does experience tell us, how is it generated and why should it be unreliable?

On the level of the individual, experience emerges when a clinician makes similar observations several times in a row. This is so persuasive that few doctors are immune to the phenomenon. Let’s assume the experience is about acupuncture, more precisely about acupuncture for smoking cessation. The acupuncturist presumably has learnt during his training that his therapy works for that indication via stimulating the flow of Qi, and promptly tries it on several patients. Some of them come back for more and report that they find it easier to give up cigarettes after consulting him. This happens repeatedly, and our clinician forthwith is convinced – in fact, he knows – that acupuncture is effective for smoking cessation.

If we critically analyse this scenario, what does it tell us? It tells us very little of relevance, I am afraid. The scenario is entirely compatible with a whole host of explanations which have nothing to do with the effects of acupuncture per se:

  • Those patients who did not manage to stop smoking might not have returned. Only seeing his successes without his failures, the acupuncturist would have got the wrong end of the stick.
  • Human memory is selective such that the few patients who did come back and reported failure might easily get forgotten by the clinician. We all remember the good things and forget the disappointments, particularly if we are clinicians.
  • The placebo-effect might have played a dirty trick on the experience of our acupuncturist.
  • Some patients might have used nicotine patches that helped him to stop smoking without disclosing this fact to the acupuncturist who then, of course, attributed the benefit to his needling.
  • The acupuncturist – being a very kind and empathetic clinician – might have involuntarily induced some of his patients to show kindness in return and thus tell porkies about their smoking habits which would have created a false positive impression about the effectiveness of his treatment.
  • Being so empathetic, the acupuncturists would have provided lots of encouragement to stop smoking which, in some patients, might have been sufficient to kick the habit.

 

The long and short of all this is that our acupuncturist gradually got convinced by this interplay of factors that Qi exists and that acupuncture is an ineffective treatment. Hence forth he would bet his last shirt that he is right about this – after all, he has seen it with his own eyes, not just once but many times. And he will doubt anyone who shows him evidence that says otherwise. In fact, he is likely become very sceptical about scientific evidence in general – just like the doctors who talked to me after my lecture.

On a population level, such experience will be prevalent in not just one but most acupuncturists. Our clinician’s experience is certainly not unique; others will have made it too. In fact, as an acupuncturist, it is hard not to make it. Acupuncturists would have told everyone else about it, perhaps reported it on conferences or published it in articles or books. Experience of this nature is passed on from generation to generation, and soon someone will be able to demonstrate that acupuncture has been used ’effectively’ for smoking cessation since decades or centuries. The creation of a myth out of unreliable experience is thus complete.

Am I saying that experience of this nature is always and necessarily wrong or useless? No, I am not. It can be and often is correct. But, at the same time, it is frequently incorrect. It can serve as a valuable indicator but not more. Experience is not a tool for reliably informing us about the effectiveness of medical interventions. Experience based-medicine is an obsolete pseudo-medicine burdened with concepts that are counter-productive to optimal health care.

Philosophers and other people who are much cleverer than I am have been trying for some time to separate good from bad science and evidence from experience. Most recently, two philosophers, MASSIMO PIGLIUCCI and MAARTEN BOUDRY, commented specifically on this problem in relation to TCM. I leave you with some extensive quotes from what they wrote.

… pointing out that some traditional Chinese remedies (like drinking fresh turtle blood to alleviate cold symptoms) may in fact work, and therefore should not be dismissed as pseudoscience… risks confusing the possible effectiveness of folk remedies with the arbitrary theoretical-metaphysical baggage attached to it. There is no question that some folk remedies do work. The active ingredient of aspirin, for example, is derived from willow bark…

… claims about the existence of “Qi” energy, channeled through the human body by way of “meridians,” though, is a different matter. This sounds scientific, because it uses arcane jargon that gives the impression of articulating explanatory principles. But there is no way to test the existence of Qi and associated meridians, or to establish a viable research program based on those concepts, for the simple reason that talk of Qi and meridians only looks substantive, but it isn’t even in the ballpark of an empirically verifiable theory.

…the notion of Qi only mimics scientific notions such as enzyme actions on lipid compounds. This is a standard modus operandi of pseudoscience: it adopts the external trappings of science, but without the substance.

…The notion of Qi, again, is not really a theory in any meaningful sense of the word. It is just an evocative word to label a mysterious force of which we do not know and we are not told how to find out anything at all.

Still, one may reasonably object, what’s the harm in believing in Qi and related notions, if in fact the proposed remedies seem to help? Well, setting aside the obvious objections that the slaughtering of turtles might raise on ethical grounds, there are several issues to consider. To begin with, we can incorporate whatever serendipitous discoveries from folk medicine into modern scientific practice, as in the case of the willow bark turned aspirin. In this sense, there is no such thing as “alternative” medicine, there’s only stuff that works and stuff that doesn’t.

Second, if we are positing Qi and similar concepts, we are attempting to provide explanations for why some things work and others don’t. If these explanations are wrong, or unfounded as in the case of vacuous concepts like Qi, then we ought to correct or abandon them. Most importantly, pseudo-medical treatments often do not work, or are even positively harmful. If you take folk herbal “remedies,” for instance, while your body is fighting a serious infection, you may suffer severe, even fatal, consequences.

…Indulging in a bit of pseudoscience in some instances may be relatively innocuous, but the problem is that doing so lowers your defenses against more dangerous delusions that are based on similar confusions and fallacies. For instance, you may expose yourself and your loved ones to harm because your pseudoscientific proclivities lead you to accept notions that have been scientifically disproved, like the increasingly (and worryingly) popular idea that vaccines cause autism.

Philosophers nowadays recognize that there is no sharp line dividing sense from nonsense, and moreover that doctrines starting out in one camp may over time evolve into the other. For example, alchemy was a (somewhat) legitimate science in the times of Newton and Boyle, but it is now firmly pseudoscientific (movements in the opposite direction, from full-blown pseudoscience to genuine science, are notably rare)….

The borderlines between genuine science and pseudoscience may be fuzzy, but this should be even more of a call for careful distinctions, based on systematic facts and sound reasoning. To try a modicum of turtle blood here and a little aspirin there is not the hallmark of wisdom and even-mindedness. It is a dangerous gateway to superstition and irrationality

Acupuncture has remained one of the most controversial topics in the area of alternative medicine. Is it plausible? Is it safe? Is it effective? The arguments have been raging for decades and are by no means settled yet. The June issue of Anesth. Analg. is partly dedicated to this debate; the editor has invited two teams of experts to put forward their contrasting views.

The team of experts arguing in support of acupuncture conclude as follows: “clinical trials support the efficacy of acupuncture in reducing post-operative nausea and vomiting and postoperative pain; however, evidence supporting acupuncture as a treatment for chronic pain conditions is mixed. It should be noted that acupuncture trials in chronic pain have concluded that acupuncture treatment is often superior to standard of care or wait list controls and that acupuncture has minimal side effects and is cost effective. Brain imaging studies have demonstrated that there are different neural correlates between verum and sham acupuncture stimulation. Additionally, all clinical trials and many research studies have assumed that the acupuncture effect is equal to the “needle” effect, failing to recognize that factors in addition to specific effects of needling are also important contributors to the therapeutic effect of acupuncture in the setting of chronic pain.

Last, acupuncture is an ancient medical intervention first developed in an era when there were no laboratory tests, technology, or science of anatomy. The reason that the practice of acupuncture has survived for thousands of years is because it has evolved over time, with changes ranging from the number of acupuncture points to the practice techniques. Instead of criticizing this ancient art with arguments culled from modern medicine and science, physicians and scientists should try to integrate current knowledge into this ancient, yet ever-evolving practice so it may be used to treat conditions for which pharmaceutical interventions are ineffective and/or potentially dangerous. Over the last decade, there has been a growing green movement and eco-sustainability trend as well as an increased awareness that the same medication may not be effective in treating every patient with the same biomedical diagnosis. This “new age-integrative medicine in Western culture promotes a patient-oriented medical practice that complements the ancient Chinese theory behind acupuncture practice. Overall, acupuncture practice should not be seen as a placebo intervention or merely a needle therapy, but a medical option that not only treats disorders but also fosters a greater awareness of how harmonic interactions between self, family, work, and environment play a role in promoting health and restoring order”.

The two experts arguing against the usefulness of acupuncture draw the following conclusions: “It is clear from meta-analyses that results of acupuncture trials are variable and inconsistent, even for single conditions.  After thousands of trials of acupuncture and hundreds of systematic reviews,arguments continue unabated. In 2011, Pain published an editorial that summed up the present situation well.

“Is there really any need for more studies? Ernst et al. point out that the positive studies conclude that acupuncture relieves pain in some conditions but not in other very similar conditions. What would you think if a new pain pill was shown to relieve musculoskeletal pain in the arms but not in the legs? The most parsimonious explanation is that the positive studies are false positives. In his seminal article on why most published research findings are false, Ioannidis points out that when a popular but ineffective treatment is studied, false positive results are common for multiple reason, including bias and low prior probability.”

Since it has proved impossible to find consistent evidence after more than 3000 trials, it is time to give up. It seems very unlikely that the money that it would cost to do another 3000 trials would be well-spent.

A small excess of positive results after thousands of trials is most consistent with an inactive intervention. The small excess is predicted by poor study design and publication bias. Furthermore, Simmons et al. demonstrated that exploitation of “undisclosed flexibility in data collection and analysis” can produce statistically positive results even from a completely nonexistent effect. They say this is “… not driven by a willingness to deceive but by the self-serving interpretation of ambiguity, which enables us to convince ourselves that whichever decisions produced the most publishable outcome must have also been the most appropriate.”

With acupuncture, in particular, there is documented profound bias among proponents. Existing studies are also contaminated by variables other than acupuncture, such as the frequent inclusion of “electroacupuncture” which is essentially transdermal electrical nerve stimulation masquerading as acupuncture.

The best controlled studies show a clear pattern, with acupuncture the outcome does not depend on needle location or even needle insertion. Since these variables are those that define acupuncture, the only sensible conclusion is that acupuncture does not work. Everything else is the expected noise of clinical trials, and this noise seems particularly high with acupuncture research. The most parsimonious conclusion is that with acupuncture there is no signal, only noise.

The interests of medicine would be best-served if we emulated the Chinese Emperor Dao Guang and issued an edict stating that acupuncture and moxibustion should no longer be used in clinical practice.

No doubt acupuncture will continue to exist on the “High Streets” where they can be tolerated as a voluntary self-imposed tax on the gullible (as long as they do not make unjustified claims).”

The readers of this blog will no doubt make up their own mind as to which arguments are stronger, more logical, more convincing, and based on more reliable evidence. I recommend reading the full articles and studying the references.

Personally, I have no hesitation in agreeing with the second, more sceptical view, and I have to admit finding the pro-acupuncture arguments weak as well as full of clichés, fallacies and errors.

I look forward to a lively discussion.

Evidence-based medicine (EBM) is a tool which enables health care professionals to optimize the chances for patients to be treated according to ethically, legally and medically accepted standards. Many proponents of alternative medicine used to reject the principles of EBM, not least because there is precious little good evidence from reliable clinical trials to support their treatments. In recent years, however, some alternative practitioners have stopped trying to swim against the tide.

They have discreetly changed their tune claiming that they do, in fact, practice EBM. Their argument usually holds that EBM represents much more than just data from clinical trials and that they actually do abide by the rules of EBM when treating their patients. The former claim is correct but the latter is not.

In order to explain why, we ought to first define our terminology. During recent years, several descriptions of EBM have become available. According to David Sackett,  who was part of the McMaster group that coined the term, EBM is “the conscientious, explicit and judicious use of current best evidence in making decisions about the care of individual patients. The practice of evidence-based medicine means integrating individual clinical experience with the best available external clinical evidence from systematic research”. As proposed by Sackett, the practice of  EBM rests on the following three pillars:

  • External Evidence– clinically relevant and reliable research mostly from clinical investigations into the efficacy and safety of therapeutic interventions – in other words clinical trials and systematic reviews. In a previous blog-post, I have elaborated on the question what evidence means.
  • Clinical Expertise– the ability to use clinical skills to identify each patient’s unique health state, diagnosis and risks as well as his/her chances to benefit from the available therapeutic options.
  • Patient Values– the individual preferences, concerns and expectations of the patient which are important in order to meet the patient’s needs.

So, how can a homeopath treating a patient with migraine, a chiropractor manipulating a child with asthma, or an acupuncturist needling a consumer for smoking cessation claim to practice EBM? The best available external evidence shows that neither of these therapies is effective. In fact, it even suggests that these options are ineffective for the above-named indications.

Using the first example of the homeopath, the scenario goes something like this: a homeopath believes in the ability of homeopathy and has the clinical expertise in it (he probably has clinical expertise in nothing else but homeopathy). His patient’s preference is very clearly with homeopathy (otherwise, she would not have consulted him). It follows that the homeopath does embrace two pillars of EBM. As to the third pillar – external evidence – he is adamant that clinical trials cannot do justice to something as holistic, subtle, individualized etc. Therefore he refuses to recognize the trial data as conclusive and rather trusts his experience which might be substantial.

I am sure that this line of arguing can convince some people; it certainly seems to appear compelling to those alternative practitioners who claim to practice EBM. However, I cannot agree with them.

The reason is simple: the practice of EBM must rest on three pillars, and each one of those three pillars is essential; we cannot just pick the ones we happen to like and drop the ones which we find award, we need them all.

We might be generous and grant that the homeopath’s pseudo-EBM argument outlined above suggests that his practice rests on two of the three pillars. However, the third one is absent and has been replaced by a bizarre imitation. To pretend that external evidence can be substituted by something else is erroneous and introduces double standards which are not acceptable – not because this would be against some bloodless principles of nit-picking academics, but because it would not be in the best interest of the patient. And, after all, the primary concern of EBM has to be the patient.

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