Feb 24 2010
The House of Commons Science and Technology Committee (STC) has released a report, Evidence Check 2: Homeopathy, in which they recommend that the NHS stop funding homeopathy. The report is a rare commodity – a thoroughly science-based political document.
The committee went beyond simply stating that homeopathy does not work, and revealed impressive insight into the ethical, practical, and scientific problems caused by NHS support for an implausible and ineffective pseudoscience.
The STC formed in October of 2009, and this is their second report. The goals of the STC itself are significant step forward:
The purpose of Evidence Check is to examine how the Government uses evidence to formulate and review its policies.
We certainly can use more of that.
What Is Homeopathy
The report is impressive in its accuracy and insight, starting with its definition of homeopathy. It states that homeopathy is:
based on two principles: “like-cures-like” whereby a substance that causes a symptom is used in diluted form to treat the same symptom in illness and “ultra-dilution” whereby the more dilute a substance the more potent it is…
That is essentially correct. “Like cures like” is another way of stating the ancient superstition of sympathetic magic – the kind of magical thinking that led some ancient cultures to believe that rhino horn is a cure for impotence because of its superficial resemblance to the erect male organ. This is a pre-scientific notion, based upon vitalism or essentialism – that substances contain an essence that can be transferred separate from their physical substance. These notions remain core to homeopathy today.
The report is also careful to state that homeopathic remedies are not the same thing as herbal remedies (a common misconception), even though sometimes they are made from herbs (which are then diluted out of existence).
Ultra-dilutions refers to the homeopathic practice of diluting substances to the point where there is no original substance left – just the water in which it is diluted. This water is then given as a remedy, either by itself or placed on a sugar pill. Dilutions of 30C, or a 1/100 dilution 30 times, or 10^60 dilution are common in homeopathy.
Some Basic Principles
The report then lays out its most basic premise, referring to the National Health Service (NHS):
You have the right to expect local decisions on funding of [...] drugs and treatments to be made rationally following a proper consideration of the evidence.
This may seem like stating the obvious, but it is this very notion – basing medical decisions on reason and evidence – that is being challenged by the so-called alternative medicine culture.
The report also addresses the issue of plausibility – something very important to science-based medicine:
Our expectation of an explanation for a mechanism of action is that it is both scientifically plausible and demonstrable.
But then they add the caveat;
Historically, some medical interventions were demonstrably effective before anyone understood their modes of action. For example, after 150 years of use, there is still debate about precisely how anaesthetics work. It is more important to know whether a treatment works—its efficacy—than how it works.
I would characterize these statements as true but incomplete. It is not necessary to know exactly how a treatment works in order to be confident that it does work – but these two things are not isolated from each other. They are both part of the overall scientific evidence needed to conclude whether or not a treatment works, and this is relevant to homeopathy. Not knowing how a treatment works in not equivalent to knowing that a treatment is highly improbable (as is the case with homeopathy). Extreme implausibility should affect where we place the threshold of clinical evidence for efficacy.
The report gives an excellent overview of the nature of clinical evidence and the pitfalls of “cherry picking” data to support a biased conclusion. They justify their reliance on meta-analysis of systematic reviews of the best randomized controlled trials.
They follow this up with a discussion of the placebo effect, and how to distinguish placebo medicine from physiologically active medicine. They give a reasonable definition of placebo:
we are attracted to the definition produced by Dr Howard Brody, Director of the Institute of Medical Humanities at the University of Texas Medical Branch, who defined the placebo effect as “a change in a patient’s illness attributable to the symbolic import of a treatment rather than a specific pharmacologic or physiologic property”. According to this definition, the placebo effect does not necessarily require a dummy treatment. It is important to remember that when patients receive an efficacious treatment, they may benefit from a placebo (non-specific) effect as well as the specific effect of the treatment. Brody’s definition also allows for a wider range of non-specific effects, such as the doctor patient relationship, to be relevant to the placebo effect.
They also address the issue of placebo medicine, quoting Edzard Ernst (an outstanding critic of unscientific medicine whose influence on the findings of the committee is clearly seen).
I would argue it is unnecessary, unreliable and unethical to prescribe placebos through the NHS; unnecessary because if you do it well then an active treatment will also generate a placebo effect. If I give my patient an aspirin for his or her headache and I do it with empathy, time and understanding this patient will benefit from the pharmacological effect of the aspirin and she will also benefit from the placebo effect through the encounter with her clinician. It is unreliable and there is lots of data to show that placebo effects are notoriously unreliable; somebody who responds today may not respond tomorrow; responses are not large in effect size and they are not usually long-lasting. Foremost, it is unethical.
Does Homeopathy Work?
At the risk, of being anti-climactic – the simple conclusion the committee comes to is -no. But they do go through their reasoning in detail. They begin with plausibility, first addressing the principle of likes-cures-like. They correctly dismiss the analogy offered by some homeopaths that like-cures-like is similar to the toxicological principle of hormesis – which essentially states that some substances which are toxic at high doses may be benign and even beneficial at low doses.
However, there are significant problems with the hormesis justification. First, it represents over-extrapolation – just because some substances may display hormesis, that does not mean that most or all substances do. And second, hormesis may apply to low doses, but that is not analogous to the ultra-dilute (essentially non-existent) doses of homeopathic remedies – low dose is not no dose. Hormesis also is not analogous to the homeopathic claim that substances behave differently in well and sick individuals.
We conclude that the principle of like-cures-like is theoretically weak. It fails to provide a credible physiological mode of action for homeopathic products. We note that this is the settled view of medical science.
Next they dismantle the notion that ultra-dilutions can still carry the essence of what was diluted in the substance. This notion has been so thoroughly discredited on this and other scientific sites, I will just jump to their conclusion:
We consider the notion that ultra-dilutions can maintain an imprint of substances previously dissolved in them to be scientifically implausible.
And next we get to the real meat of the report – evidence for efficacy. The committee listened to proponents and critics, and found that homeopathy proponents cherry picked out-dated and fatally flawed studies to support their position, including a lecture series that wasn’t even a systematic review.
Meanwhile, the best reviews of the best evidence clearly show that homeopathy is no better than placebo – which means it doesn’t work. They conclude:
In our view, the systematic reviews and meta-analyses conclusively demonstrate that homeopathic products perform no better than placebos. The Government shares our interpretation of the evidence. We asked the Minister, Mike O’Brien, whether the Government had any credible evidence that homeopathy works beyond the placebo effect and he responded: “the straight answer is no”.
And then here is the zinger:
We regret that advocates of homeopathy, including in their submissions to our inquiry, choose to rely on, and promulgate, selective approaches to the treatment of the evidence base as this risks confusing or misleading the public, the media and policymakers.
That in our criticism of unscientific medicine in a nutshell. SBM is primarily about methodology, not a set of beliefs or conclusions. SBM is the application of fair and rigorous scientific methods to assessing treatments and medical interventions. The only “alternative” to SBM is not fairly and rigorously applying scientific methods. This includes the kind of biased cherry picking for which the STC now criticizes homeopaths.
Many of us on SBM have pointed out before that the common ploy of alternative medicine proponents is to take a weak study, or a study that was clearly negative, and then conclude that even though the study was negative, it shows promise, and therefore we need to fund more research. This creates an endless succession of weak or negative research, calling for more research. The purpose seems to be to use the fact that a modality is being researched as a marketing tool, without ever discarding a modality due to negative research.
At some point, however, it must be reasonable to cross a threshold where we can conclude that there has been enough research and the medical community, with its limited research money, should simply move on. With homeopathy we have a highly implausible treatment that should not work, and the evidence shows convincingly that it in fact does not work. Homeopaths have had 200 years to make their scientific case, and they have completely failed. It is time to move on.
The STC agrees:
There has been enough testing of homeopathy and plenty of evidence showing that it is not efficacious. Competition for research funding is fierce and we cannot see how further research on the efficacy of homeopathy is justified in the face of competing priorities.
In fact, they go further to say that it is unethical to enroll patients into a research study of a treatment that we already know does not work.
Given the soundly negative evaluation of the plausibility and efficacy of homeopathy, and the rejection of placebo medicine, it is no surprise that the STC recommended that the NHS stop funding homeopathy completely. This would include closing, or at least withdrawing funding for, the four homeopathic hospitals in the UK. They further recommend withdrawing licensing by the MHRA (the UK equivalent of the FDA):
We conclude that the MHRA should seek evidence of efficacy to the same standard for all the products examined for licensing which make medical claims and we recommend that the MHRA remove all references to homeopathic provings from its guidance other than to make it clear that they are not evidence of efficacy.
Imagine that – applying a single consistent scientific standard to all claims of efficacy.
The NHS spends about 4 million pounds a year on homeopathy (this is direct costs, and does not include maintenance costs for homeopathic hospitals). This is not much, but any money spent on nonsense is a waste of tax money citizens place in the trust of their government.
The implications of these recommendations go beyond the NHS. They further recommend that EU countries who support homeopathy, such as Germany and France, reconsider their own support for this dubious pseudoscience. It is also quite possible that the withdrawal of official government approval of homeopathy will have a ripple effect, leading major pharmacies to stop carrying homeopathic products.
The STC correctly observes that when the government supports a specific treatment, by either paying for it or for research, this becomes a tacit endorsement of the product or service in the eyes of the public. Therefore, they have a responsibility to get the science right.
Defenders of homeopathy are, of course, not happy with the findings of the STC. I find it amusing that in various news article defenders respond to the accusation that homeopathy supporters use deception and misdirection, by using deception and misdirection. For example, in the Times Online:
Robert Wilson, chairman of Nelsons, Britain’s largest manufacturer of natural healthcare products, said: “There is good evidence that homeopathy works beyond placebo, for example in animals and babies.”
The assumption here is that any effect in a baby or animal cannot be due to the placebo effect, because placebo effects are dependent upon the expectation of benefit. This is a gross misconception, however. Placebo effects can result from the attention of the caregiver or other non-specific effects. Or they can simply be an artifact of observation – the person observing for an effect in the animal or baby may be the one responding to the placebo.
The above statement is simply false – there is no good evidence for the effectively of any homeopathic remedy in any population.
Prince Charles is a big supporter of homeopathy, and representative of his foundation to promote alternative medicine were quoted by the New Scientist:
“For patients suffering from long term disease, where no scientific, evidence based medicine can offer effective treatment, it does not matter how it works,” says the foundation, in a response to the committee’s report. “What matters to them is whether they get better, whether pain and other symptoms are alleviated.”
Michael Dixon, medical director of the foundation adds: “Science is a vital tool in healthcare, but so are compassion and caring and treating patients with dignity. It is not clear that the Committee took that into account.”
The report addressed and dismissed the notion of placebo medicine quite well. But we also see here some common ploys. The first sentence justifies using implausible and ineffective treatments simply because there may not be another alternative – but this is no justification. Resorting to an ineffective treatment will not help someone suffering from an untreatable ailment – it will simply add insult to injury. The statement also begs the question – assuming that patients “get better.” However, it is only through rigorous scientific research that we can know if anyone does benefit from a treatment – and the evidence clearly shows that there is no benefit from homeopathy.
The second statement by Michael Dixon is a despicable bit of bad logic, but also not uncommon. It is primarily a non sequitur – treating patients with compassion and dignity does not alter the scientific evidence. It is also a false dichotomy – as if you cannot have science-based medicine and compassionate medicine at the same time.
Further, I would argue that the most compassionate, caring, and dignified treatment a physician can give a patient is to give them proper informed consent and to prescribe treatments which are actually safe and effective. Using ineffective and implausible treatments is the most uncaring thing a physician can do, and prescribing placebos as if they were real medicine is an assault on the dignity of a patient.
The STC report is an impressive document defending many of the core principles of science-based medicine and rational regulation of medical practice and products. If the document were crafted by the authors of SBM itself I do not think we could have improved much upon it.
It remains to be seen what impact it will have – we can only hope that it is extensive and immediate.
It is heartening that a political body can thoroughly review the evidence, receiving testimony offering differing opinions, and come to a so thoroughly science-based conclusion. Its condemnation of homeopathy and the behavior of homeopaths is accurate and devastating.
I would like to see the recommendations replicated in the US and elsewhere. The FDA, for example, should withdraw its automatic approval of the homeopathic pharmacopoeia.
But perhaps even more important than its potential effect on homeopathy specifically, is the potential for this type of analysis, and the basic principles expressed in the report, to be applied to all of medicine. The committee’s report is a devastating condemnation of the foundations of so-called complementary and alternative medicine, smashing many of its pillars.
Perhaps the looming health care crisis and the attention that rising health care costs is currently receiving will make this kind of no-nonsense rigorous scientific assessment fashionable in Western politics. Removing worthless modalities from the health care system is certainly in the interests of efficiency and cost-effectiveness.
As the STC also points out – for the public to have faith in government regulation of health care, and for that trust not to be abused, government has a responsibility to be rigorously evidence-based. They conclude:
By providing homeopathy on the NHS and allowing MHRA licensing of products which subsequently appear on pharmacy shelves, the Government runs the risk of endorsing homeopathy as an efficacious system of medicine. To maintain patient trust, choice and safety, the Government should not endorse the use of placebo treatments, including homeopathy. Homeopathy should not be funded on the NHS and the MHRA should stop licensing homeopathic products.
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