Oct 25 2010

A Post-Modernist Response to Science-Based Medicine

I receive frequent commentary on my public writing, which is great. The feature that most distinguishes blogs is that they are conversations. So I am glad to see that science-based medicine (a term I coined) is getting targeted for criticism in other blogs. One blogger, Marya Zilberberg at Healthcare, etc., has written a series of posts responding to what she thinks is our position at Science-based medicine. What she has done, however, is make many of the logical fallacies typically committed in defense of unscientific medical modalities and framed them as one giant straw man.

She is partly responding to this article of mine on SBM (What’s the harm) in which I make the point that medicine is a risk vs benefit game. Ethical responsible medical practice involves interventions where there is at least the probability of doing more benefit than harm with proper informed consent, so the patient knows what those chances are. Using scientifically dubious treatments, where there is little or no chance of benefit, especially when they are overhyped, is therefore unethical. And further, the “harm” side of the equation needs to include all forms of harm, not just direct physical harm.

Zilberberg’s response is the typical tu quoque logical fallacy – well, science-based medicine is not all it’s cracked up to be either, so there. She writes:

Now, let’s get on to “proof” in science-based medicine. As you well know, while we do have evidence for efficacy and safety of some modalities, many are grandfathered without any science. Even those that are shown to have acceptable efficacy and safety profiles as mandated by the FDA, are arguably (and many do argue) not all that. There is an important concept in clinical science of heterogeneous response to treatment, HTE, which I have addressed extensively on my blog. I did not make it up, it is very real, and it is this phenomenon that makes it difficult to predict how an individual will respond to a particular intervention. This confounds much of what we think is God’s own word on what is supposed to work in allopathic medicine.

This is also the fallacy of the perfect solution – since science-based medicine is not perfect, there is no legitimate basis for criticism of any modality. This is also premised on the false dichotomy of “allopathic medicine” (a derogatory term only used, in my experience, by defenders of dubious medicine) vs “alternative” medicine (which I will refer to as CAM for short). I and others at SBM have been clear that we eschew this false dichotomy. There is only medicine with varying degrees of plausibility and evidence – there is a continuum, and we advocate always using the best that is available. We also think there should be a minimum standard, a fuzzy line of plausibility and evidence below which treatments should only be given with proper informed consent as part of an approved clinical trial. And a further line below which even research is unethical because there is no plausible potential for benefit.

These principles are, in fact, already part of ethical medicine. We did not invent these concepts. It is, rather, the proponents of CAM who wish to do away with this ethical standard – to create a false dichotomy in order to establish a double standard. We are not trying to create a new standard, just to do away with the double standard of CAM.

She refers to the heterogeneous response to treatment, again as if realization of this basic fact is not already part of science-based medicine. I, in fact, explain this to patients all the time. Our knowledge of treatments are based upon statistics, but we can never know ahead of time how an individual patient will respond. What’s the alternative? Until we get better at predicting individual response (which really will just be another application of statistics), this is the best we can do. That is why you monitor the individual response to any treatment, and act accordingly. This is basic medical student stuff, but Zilberberg acts as if this is a big revelation for science-based medicine.

We at SBM advocate for the highest scientific standards of medicine, and apply that across the board – including with pharmaceutical companies, surgeons, and anything else that is labeled as “mainstream.” Again – we do not make false categories and distinctions. It is all medicine.

The reference to “God’s own word” is an obvious allusion to the bad-old-days of paternalistic medicine (dead and buried for decades now), or the TV caricature of a doctor with a God complex. This is a typical ploy – portray any attempt at defending a scientific standard in medicine as paternalistic arrogance. In fact, Zilberberg dedicates an entire blog post to this fallacy. She writes:

First of all, it is my belief that all interventions should be approached with equanimity, if not equipoise. Although I am quite dubious that either healing crystals or Reiki can produce actual results, I do not want to confuse the absence of any evidence to this effect with the evidence of absence of the effect. Although I am not that interested in allocating resources to studying these fields, it would be paternalistic of me to bar their further investigation. So the society can decide what it wants to do with them, and in the meantime every individual can make her/his own choice whether to spend their money on them.

This is clearly where we differ. I do think, from reading her writing, that Zilberberg means well and is sincere in her positions (unlike some I criticize who I feel are just to sell something). But notice the logical contortions in her position – she wants “equipoise” with regard to all interventions, and would not dare dictate how research money is spent. I should point out that there is a range of opinions on SBM when it comes to regulation – so we are not a united front on this score. We range from libertarians who think that we should educate the public and professionals, but are against laws that would restrict access to unscientific modalities. Essentially, people have the right to make stupid decisions. Others believe that there needs to be a minimum safety net against fraud and quackery, and in fact the public wants there to be one and believes there already is one. I don’t want to get bogged down in this debate on this blog entry – I am just pointing out that Zilberberg’s premise is overly simplistic and paints with too broad a brush.

But the real point here is that she is taking an almost post-modernist position that we need to approach all claims in medicine with “equipoise.” She says that society can decide how research money is spent, even if she would not personally research an implausible topic. Depending upon how you slice it, this is not necessary far off from my position. If people want to raise money to research an implausible question they should go right ahead. I never proposed banning implausible research. My position, rather, is that we should not waste limited public/government research resources on highly implausible modalities.

I would also add, however, that once you start doing research on humans there is a host of ethics that also come into play. In human research it is the accepted ethical standard that subjects should at least have a chance of benefiting from the treatments being studied, or at least there should be a greater chance of benefit than harm. I don’t see how this ethical standard can be met with homeopathy, for example, where there is essentially zero chance of benefit. At some point you pass a line of infinitessimal plausibility where the ethics become problematic.

Zilberberg then makes the “absence of evidence vs evidence of absence” mistake – really and oversimplification of this concept to the point of being wrong. While it is true that the absence of evidence if not necessarily evidence of absence – it can be, depending upon how thoroughly you have looked. If I search my house for a specific item and don’t find it, that is pretty good evidence that it’s not there. It is not “proof” of absence, but it is evidence. With many of the modalities that Zilberberg admits she is personally dubious about there is evidence of absence of an effect. This evidence comes in two forms – all of the science that tells us the modalities are highly implausible, and often there is clinical evidence of lack of an effect. To pretend otherwise is dishonest – it is hiding from the facts out of political correctness.

Further, our patients do not want equipoise from us. They want our informed opinion. When patients ask me if they should take a homeopathic remedy I don’t give them a wishy washy answer. I give them my informed opinion, and they are grateful to have it. In the comments to her blog a commenter speculates about my bedside manner, assuming, essentially, that I must be a paternalistic ass. This is the typical cardboard caricature I encounter, and it has no relationship to reality. It is possible to give patients useful information without being judgmental. To give them informed consent (how do you do this, by the way, without giving them information?) but understand that they will make up their own minds. Patients are in charge of their own health care, and our job as clinicians, more than ever, is to give them the information and perspective they need to make good decisions. This does not demand “equipoise”, but evidence and perspective. In my opinion equipoise in the face of ridiculously implausible claims and evidence of lack of efficacy is a disservice to patients and a violation of trust.

Ironically, Zilberberg concludes:

Bottom line, we need to appreciate that none of the science is all that straightforward. Let us not dumb down the arguments and create false dichotomies. If we do, no one wins.

Does she actually read science-based medicine? I am left to wonder – since we regularly argue for the complexity of the science of medicine. I want people to understand how complex the relationship is, so they are not shocked every time conflicting studies come out. Medical science is a messy business, and it is challenging often to infer what the best approach is. I want the profession and the public to have a much more nuanced understanding of medical science, and for the media to do a better job of representing it.

This is especially true since we do not have a paternalistic system. Patients are partners in their own health care, and therefore it helps me do my job when they understand the science that underpins medicine.

Zilberberg’s position is anti-science, although perhaps not deliberately so. It is anti-science in a post-modernist sense. She points out all the limitations of science, as if that means we cannot come to any meaningful decision, and therefore must treat all claims as equal. But all claims are not equal. Even the best are imperfect, but we can still apply science and evidence to make informed decisions about the probability of risk vs benefit. And there are some claims that are so against science and evidence (like homeopathy) that any stance other than rejection is a violation, in my opinion, of medical ethics and the trust that society places in medical professionals.

In Zilberberg’s world, however, any such judgments are the equivalent of pronouncing that these treatments over here in pile A are deemed “scientific” (as if by the word of God) and are accepted. And these over here in pile B are deemed “nonsense” and are to be ridiculed. But the false dichotomy is in her mind, not in science-based medicine. We are the ones railing against the false dichotomy – that of CAM which seeks to create a double standard. All we advocate is one consistent standard of science and evidence when evaluating all medical claims, and the rational application of science to the practice of medicine.

One final note – I would much prefer to have a conversation with the critics of science-based medicine that does not constantly involve defending SBM and myself from false accusations of arrogance and paternalism. I think it says a lot about their intellectual position when that is constantly the best they have.

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