Oct 29 2007
As I discussed on Friday, last week I was part of a panel discussion on homeopathy hosted by UCONN. It was an interesting experience, as I knew it would be. In part I of my report from the conference I talked about the plausibility arguments against homeopathy and Dr. Rustom Roy’s unconvincing response. Today I will complete my report, discussing the clinical evidence.
Donald Marcus from Baylor did an excellent job of presenting a review of the clinical evidence for homeopathy, accurately conveying that the evidence is largely negative. Iris Bell, a protege of Andrew Weil from the University of Arizona, had the job of distorting and cherry picking the clinical evidence to make is seem as if it supports homeopathy. Her strategy was typical, standard fare for CAM proponents.
First, she argued that we should accept clinical observations as reliable evidence. These are open-label or uncontrolled case reports, essentially the clinical experience of homeopaths. This is all a fancy way of saying anecdotal evidence, which over a century of scientific medicine has taught us is completely unreliable. I think anecdotes are worse than unreliable – they tend to lead us to conclusions we wish to be true rather than those that are true, and they can cause a false sense of confidence in the unwary.
It is not a surprise that homeopaths think their treatments work. As unreliable as anecdotal experience is, it is especially so if it confirms the beliefs of an ideological group desperate for recognition and legitimacy, and further a group dedicated to one treatment modality. (I don’t trust the experience of cardiac surgeons with cardiac surgery.) And to put one more nail in this coffin, I especially don’t trust the subjective experience of a group of practitioners that decidedly lack a scientific tradition.
Only data that is controlled sufficiently to minimize the effects of bias should be even considered, and certainly should trump any uncontrolled observations. Here Dr. Bell had to admit that the results of double-blind studies in homeopathy are mixed and are insufficient to demonstrate that homeopathy works for any specific indication. Even this soft condemnation is too generous, however. If one looks at the entirety of homeopathy clinical literature, we see a clear pattern that the better the study the smaller the effect, and the best studies tend to be negative. This is the pattern of pure noise with no signal – in other words, homeopathy does not work.
Dr. Bell tries to rescue homeopathy from this negative data in two primary ways. The first is to falsely present negative data as if it were positive. She does this using the Texas sharpshooter fallacy – shooting the side of a barn at random then drawing a bull’s-eye around the bullet holes. In research, this translates to looking for anomalies in the noise of the data and then claiming after the fact that it is significant. Dr. Bell presents a study with homeopathic dust mites (slide 93 in the presentation), which was negative in that there was no significant difference in the clinical outcomes. However, the outcomes for the treatment arm showed more oscillations than the placebo arm – again, even though the total outcome showed no difference. Dr. Bell concludes, using post-hoc reasoning, that this indicates biological activity in the homeopathic treatment. Voila – a negative study shows biological activity.
The second strategy was to claim that the randomized controlled trials were not adequate, primarily because they did not allow the homeopathic treatment to be individualized to the subjects. Homeopathic treatment treats the whole person, not a disease or symptom, and without individualization the study is not a test of true homeopathic treatment. This is, of course, hogwash. If there is any biological activity in homeopathic treatment, that would produce an effect that can be measured. Further, the principle of “like cures like” contradicts this whole-person defense. An extreme dilution of a substance should treat the symptoms it causes in higher dose, according to homeopathic philosophy. If this has any truth, we should be seeing some signal in the studies done so far, but we aren’t.
These objections are similar to the ones we hear from CAM in general, such as acupuncture. Current studies are never good enough (once they are negative). Positive studies are still touted, despite the same limitations.
What is likely to happen is what is happening with acupuncture studies – the complaints of the advocates will be catered to in future studies. If these studies are well designed and executed, I predict they will be negative, and then homeopaths will find some excuse to dismiss them (while cherry picking and touting any that happen to be positive, regardless of their weaknesses).
All of this amounts to advocating allowing lower quality evidence that supports homeopathy while rejecting negative evidence as not being high quality enough. Simultaneously, I might add (especially during the Q&A) criticizing the standards of evidence in mainstream scientific medicine. It seems that homeopaths would like to apply whatever standard they wish ad hoc.
Far worse than Dr. Bell was Andre Saine N.D. from the Canadian Academy for Homeopathy. He presented the epidemiological evidence for homeopathy, which amounted to 150-year-old unverified anecdotes. He presented the reports of homeopaths from the mid-1800s claiming they cured cholera, pneumonia, and rabies as if it were reliable evidence. Dr. Saine would have us believe that we can verify such a cold trail of highly dubious self-serving reports. Again we see a desperate plea to lower the bar for scientific evidence so as to admit homeopathy.
D r. Saine’s presentation degenerated into a sales pitch for homeopathy that would make any sideshow barker proud. He assured us that homeopathy is more effective than standard medicine and can cure just about anything, magically free from any side effects. He even claims that homeopathy can cure rabies with 100% success. Rabies is almost 100% fatal, even with modern treatment, so this is quite an astounding claim. An audience member helpfully suggested that we can test this claim on animals that contract rabies, since they are just put to death in any case. I pointed out that if Dr. Saine’s claims are even remotely true it is amazing that such a simple study has not been done in the last two centuries, that we have been sitting on a cure for such a deadly disease all this time and yet homeopaths have never been able to silence critics with a controlled experiments. I also pointed out that homeopathically treating “rabies,” a disease, contradicts Dr. Bell’s “holistic” defense, but that’s a separate point.
I humbly suggested that we have not seen such a study – that would dramatically silence any skepticism about homeopathy – because homeopathy does not work, and Dr. Saine’s century and a half old anecdotes are perhaps not reliable. This prompted the audience member to ask me if such a study were done and cure rabies would I be converted to a believer in homeopathy. I responded in the affirmative, with the appropriate caveats about study design and transparency, but also turned the question around. If such a study is negative would the audience member then doubt the effectiveness of homeopathy.
I found it ironic that she felt she should ask me that question, definitely implying (and the audience generally agreed) that it is the proponents of scientific medicine who are closed-minded. Yet we are the ones who are constantly in a state of reevaluating our claims and treatments based upon new evidence, and actually change our practice. Homeopaths are clinging to a 200-year-old disproven system of medicine and refuse to change in the face of new evidence. But she did not feel it necessary to challenge the homeopaths with such a question, as I did.
I also pointed out that despite hundreds of millions of dollars spent by NCCAM on alternative modalities, despite numerous studies, there has yet to be a single alternative modality that is rejected by its proponents. Until one single CAM modality is rejected based upon evidence of lack of efficacy, they collectively have no claim to being scientific or evidence-based. All CAM research is a sham and a waste until this happens.
The audience was hopeful – hopeful for the promise of homeopathy, for collaboration with skeptical scientists, with ultimate vindication. They beamed with the hope that UFO enthusiasts had 40 years ago that proof was just around the corner (and each new generation finds and loses for themselves). They made all the arguments of the ESP researchers who want to prematurely declare their discipline legitimate, and who blame all the negativity on the closed-mindedness of skeptics.
It was very hard for me not to show the “been there, done that” reaction that I had sitting in that room, hearing all the tired excuses and logical fallacies over again. But I think I pulled it off. Even the dedicated homeopaths, by the end, seemed to at least think that I was an exception (and they said so every time I displayed a trait they thought absent in their ideological enemies). They clearly entered the forum thinking that homeopathy skeptics were closed-minded, dismissive, and practitioners of corporate, drug shilling medicine. What they met were a couple of academic physicians just trying to honestly defend the scientific standards of medicine. We weren’t the bogey men they imagined, so we must (in their minds) be exceptions to the rule.
While I don’t think I changed any minds on homeopathy (and the poll that was conducted on the live webcast indicates this; it was 90% pro-homeopathy before and after the conference) it was an interesting window into the current claims of its proponents. It also clearly showed the depth of the problem. The hardcore believers are buried beneath an increasingly sophisticated mound of nonsense. The “water memory” data were little more than a smoke screen behind which homeopaths can hide. The clinical data are negative, but clinical data are also complex enough to be easily twisted to the desires of ideologues.
I have as little hope that proponents will abandon homeopathy as creationists will accept evolution. The purpose of skeptical attention, however, is to be a watchdog on such anti-scientific or pseudoscientific ideologues, to keep them on the margins and to make sure that their false claims do not go unanswered.
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