MD, PhD, FMedSci, FRSB, FRCP, FRCPEd

critical thinking

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.

It is not often that we see an article of the great George Vithoulkas, the ‘über-guru‘ of homeopathy, in a medical journal. In fact, this paper, which he co-authored with several colleagues, seems to be a rare exception: in his entire career, he seems to have published just 15 Medline- listed articles most of which are letters to the editor.

According to Wikipedia, Vithoulkas has been described as “the maestro of classical homeopathy” by Robin Shohet; Lyle Morgan says he is “widely considered to be the greatest living homeopathic theorist”; and Scott Shannon calls him a “contemporary master of homeopathy.” Paul Ekins credited Vithoulkas with the revival of the credibility of homeopathy.

In his brand new paper, Vithoulkas provides evidence for the notion that homeopathy can treat infertility. More specifically, the authors present 5 cases of female infertility treated successfully with the use of homeopathic remedies.

Really?

Yes, really! The American Medical College of Homeopathy informs us that homeopathy has an absolute solution that can augment your probability of conception. Homeopathic treatment of Infertility addresses both physical and emotional imbalances in a person. Homeopathy plays a role in treating Infertility by strengthening the reproductive organs in both men and women, by regulating hormonal balance, menstruation and ovulation in women, by escalating blood flow into the pelvic region, by mounting the thickness of the uterine lining and preventing the uterus from contracting hence abating chances of a miscarriage, and by increasing quality and quantity of sperm count in men. It can also be advantageous in reducing anxiety so that the embryo implantation can take place in a favourable environment. Homoeopathy is a system of medicine directed at assisting the body’s own healing process.

Imagine: the 5 women in Vithoulkas ‘study’ wanted to have children; they consulted homeopaths because they did not get pregnant in a timely fashion. The homeopaths prescribed individualised homeopathy and treated them for prolonged periods of time. Eventually, BINGO!, all of the 5 women got pregnant.

What a hoot!

It beggars belief that this result is being credited to the administration of homeopathic remedies. Do the authors not know that, in many cases, it can take many months until a pregnancy occurs? Do they not think that the many women they treated unsuccessfully for the same problem should raise some doubts about homeopathy? Do they really believe that their remedies had any causal relationship to the 5 pregnancies?

Vithoulkas was a recipient of the Right Livelihood Award in 1996. I hope they did not give it to him in recognition of his scientific achievements!

 

 

Mohamed Khalifa is a therapist who works in Austria and has been practicing manual therapy for more than 30 years. His treatment, the so-called “Khalifa therapy”, is based on rhythmically applying manual pressure on parts of the body. Khalifa claims to be able to speed the self-healing processes of the human body. He has treated many top-athletes from all over the world; however, his method has never been investigated in detail within interdisciplinary scientific studies.

Now the first RCT of Khalifa therapy has become available.

Rupture of the anterior cruciate ligament (ACL) is an injury which usually needs to be treated surgically. It does not heal spontaneously, although some claim this commonly accepted knowledge to be not true. This randomized, controlled, observer-blinded, multicentre study was performed to test the effectiveness of Khalifa therapy for ACL. Thirty patients with complete ACL rupture, magnetic resonance imaging (MRI) verified, were included. Study examinations (e.g., international knee documentation committee (IKDC) score) were performed at inclusion (t 0). Patients were randomized to receive either standardised physiotherapy (ST) or additionally 1 hour of Khalifa therapy at the first session (STK). Twenty-four hours later, study examinations were performed again (t 1). Three months later control MRI and follow-up examinations were performed (t 2).

Initial status was comparable between both groups. There was a highly significant difference of mean IKDC score results at t 1 and t 2. After 3 months, 47% of the STK patients, but no ST patient, demonstrated an end-to-end homogeneous ACL in MRI. Clinical and physical examinations were significantly different in t 1 and t 2. ACL healing can be improved with manual therapy. Physical activity could be performed without pain and nearly normal range of motion after one treatment of specific pressure.

The authors of this study concluded that spontaneous healing of ACL rupture is possible within 3 months after lesion, enhanced by Khalifa therapy. The effect sizes of 1.6 and 2.0 standard deviations after treatment and after 3 months are considerable and prompt further work. Further progress in understanding the underlying mechanisms including placebo will be possible when more experience with the manual pressure therapy has been gathered by other therapists.

The authors of this RCT state that according to common knowledge, it (ACL) does not heal spontaneously. Other authors disagree with this notion:

Observations on 14 patients with ACL, for instance, indicated an acutely injured ACL may eventually spontaneously heal without using an extension brace, allowing return to athletic activity. Another study suggested that an acutely injured ACL has healing capability. It also suggests that conservative management of the acute ACL injury can yield satisfactory results in a group of individuals who have low athletic demands and continuous ACL on MRI, provided the patients are willing to accept the slight risk of late ACL reconstruction and meniscal injury.

So yes, the authors of the new RCT are correct in stating: spontaneous healing of ACL rupture is possible within 3 months … but the healing might indeed be SPONTANEOUS, i.e. unrelated to the Khalifa therapy. Before we can accept that Khalifa therapy is anything but a theatrical placebo, this RCT needs independent replication. Generally speaking, it seems a bad idea to make exaggerated claims on the basis of one single trial, particularly for treatments that are as implausible as this one.

Homeopathy is a deeply puzzling subject for many observers. Perhaps it gets a little easier to understand, if we consider the three main perspectives on homeopathy. For the purpose of this post, I take the liberty of exaggerating, almost caricaturizing, these perspectives in order to contrast them as clearly as possible.

THE SCEPTICS’ PERSPECTIVE

Sceptics take a brief look at the two main assumptions which underpin homeopathy (like cures like and potentiation/dilution/water memory) and henceforward are convinced that homeopathic remedies are pure placebos. Homeopathy flies in the face of science; if homeopathy is right, several laws of nature must be wrong, they love to point out. As this is most unlikely, they reject homeopathy outright, usually even without looking in any detail at what homeopaths consider to be evidence in support of their trade. If sceptics are forced to consider a positive study of homeopathy, they know before they have seen it that its results are wrong – due to an error caused by chance, faulty study design or fabrication. The sceptics’ conclusion on homeopathy: it is a placebo-therapy, no doubt about it; and further investment into research is a waste of scarce resources which must be stopped.

THE BELIEVERS’ PERSPECTIVE

The believers in homeopathy know from experience that homeopathy works. They therefore feel that they have no choice but to reject almost every word the sceptics might tell them. They cling on to the gospel of Hahnemann and elaborate on the modern but vague theories that might support the theoretical assumptions of homeopathy. They point to positive clinical trials and outcome studies, to 200 years of experience, and to the endorsement of homeopathy by VIPs. When confronted with the weaknesses of their arguments, they find even weaker ones, such as ‘much of conventional medicine is also not based on good evidence, and the mechanism of action of many mainstream drugs is also not fully understood’. Alternatively, they employ the phoniest argument of them all: ‘even if it works via a placebo effect, it still helps patients and therefore is a useful therapy’. When even this fails, they tend to resort to ad hominem attacks against their opponents. The believers’ conclusion on homeopathy: it is unquestionably a valuable type of therapy regardless of what anyone else might say; research is merely needed to confirm their belief.

THE PERSPECTIVE OF THE ADVOCATES OF EVIDENCE-BASED MEDICINE (EBM)

The perspective of EBM-advocates is pragmatic; they simply say: “show me the evidence!” If the majority of the most reliable clinical trials of homeopathic remedies (or anything else) suggests an effect beyond placebo, they conclude that they are effective. If that is not the case, they doubt the effectiveness. If the evidence is highly contradictory or incomplete, they are likely to advocate more rigorous research. Advocates of EBM are usually not all that concerned by the lack of plausibility of the interventions they evaluate. If it works, it works, they think – and if a plausible mechanism is currently not available, it might be found in due course. The advocates of EBM have no preconceived ideas about homeopathy. Their conclusion on homeopathy goes exactly where the available best evidence leads them.

COMMENT

The arguments and counter-arguments originating from the various perspectives would surely continue for another 200 years – unless, of course, two of the three perspectives merge and arrive at the same or very similar conclusions. And this is precisely what has now happened. As I have pointed out in a recent post, the most thorough and independent evaluation of homeopathy according to rigorous EBM-standards has concluded that “the evidence from research in humans does not show that homeopathy is effective for treating the range of health conditions considered.”

In other words, two of the three principal perspectives have now drawn conclusions which are virtually identical: there is a consensus between the EBM-advocates and the sceptics. This isolates the believers and renders their position no longer tenable. If we furthermore consider that the believers are heavily burdened with obvious conflicts of interest, while the other two groups are by definition much more independent and objective, it appears more and more as though homeopathy is fast degenerating into a cult characterised by the unquestioning commitment and unconditional submission of its members who are too heavily brain-washed to realize that their fervour has isolated them from the rational sections of society. And a cult is hardly what we need in heath care, I should think.

It seems to me therefore that these intriguing developments might finally end the error that homeopathy represented for nearly 200 years.

Progress at last?

Recently, I have been invited by the final year pharmacy students of the ‘SWISS FEDERAL INSTITUTE OF TECHNOLOGY ZURICH‘ to discuss alternative medicine with them. The aspect I was keen to debate was the issue of retail-pharmacists selling medicines which are unproven or even disproven. Using the example of homeopathic remedies, I asked them how many might, when working as retail-pharmacists, sell such products. About half of them admitted that they would do this. In real life, this figure is probably closer to 100%, and this discrepancy may well be a reflection of the idealism of the students, still largely untouched by the realities of retail-pharmacy.

In our discussions, we also explored the reasons why retail-pharmacists might offer unproven or disproven medicines like homeopathic remedies to their customers. The ethical codes of pharmacists across the world quite clearly prohibit this – but, during the discussions, we all realised that the moral high ground is not easily defended against the necessity of making a living. So, what are the possible motivations for pharmacists to sell bogus medicines?

One reason would be that they are convinced of their efficacy. Whenever I talk to pharmacists, I do not get the impression that many of them believe in homeopathy. During their training, they are taught the facts about homeopathy which clearly do not support the notion of efficacy. If some pharmacists nevertheless were convinced of the efficacy of homeopathy, they would obviously not be well informed and thus find themselves in conflict with their duty to practice according to the current best evidence. On reflection therefore, strong positive belief can probably be discarded as a prominent reason for pharmacists selling bogus medicines like homeopathic remedies.

Another common argument is the notion that, because patients want such products, pharmacists must offer them. When considering it, the tension between the ethical duties as a health care professional and the commercial pressures of a shop-keeper becomes painfully obvious. For a shop-keeper, it may be perfectly fine to offer all products which might customers want. For a heath care professional, however, this is not necessarily true. The ethical codes of pharmacists make it perfectly clear that the sale of unproven or disproven medicines is not ethical. Therefore, this often cited notion may well be what pharmacists feel, but it does not seem to be a valid excuse for selling bogus medicines.

A variation of this theme is the argument that, if patients were unable to buy homeopathic remedies for self-limiting conditions which do not really require treatment at all, they would only obtain more harmful drugs. The notion here is that it might be better to sell harmless homeopathic placebos in order to avoid the side-effects of real but non-indicated medicines. In my view, this argument does not hold water: if no (drug) treatment is indicated, professionals have a duty to explain this to their patients. In this sector of health care, a smaller evil cannot easily be justified by avoiding a bigger one; on the contrary, we should always thrive for the optimal course of action, and if this means reassurance that no medical treatment is needed, so be it.

An all too obvious reason for selling bogus medicines is the undeniable fact that pharmacists earn money by doing so. There clearly is a conflict of interest here, whether pharmacists want to admit it or not – and mostly they fail to do so or play down this motivation in their decision to sell bogus medicines.

Often I hear from pharmacists working in large chain pharmacies like Boots that they have no influence whatsoever over the range of products on sale. This perception mat well be true. But equally true is the fact that no health care professional can be forced to do things which violate their code of ethics. If Boots insists on selling bogus medicines, it is up to individual pharmacists and their professional organisations to change this situation by protesting against such unethical malpractice. In my view, the argument is therefore not convincing and certainly does not provide an excuse in the long-term.

While discussing with the Swiss pharmacy students, I was made aware of yet another reason for selling bogus medicines in pharmacies. Some pharmacists might feel that stocking such products provides an opportunity for talking to patients and informing them about the evidence related to the remedy they were about to buy. This might dissuade them from purchasing it and could persuade them to get something that is effective instead. In this case, the pharmacist would merely offer the bogus medicine in order to advise customers against employing it. This strategy might well be an ethical way out of the dilemma; however, I doubt that this strategy is common practice with many pharmacists today.

With all this, we should keep in mind that there are many shades of grey between the black and white of the two extreme attitudes towards bogus medicines. There is clearly a difference whether pharmacists actively encourage their customers to buy bogus treatments (in the way it often happens in France, for instance), or whether they merely stock such products and, where possible, offer responsible, evidence-based advise to people who are tempted to buy them.

At the end of the lively but fruitful discussion with the Swiss students I felt optimistic: perhaps the days when pharmacists were the snake-oil salesmen of the modern era are counted?

As promised in the last post, I will try to briefly address the issues which make me uncomfortable about the quotes by Anthony Campbell. Readers will recall that Campbell, an ex-director of what was arguably the most influential homeopathic hospital in the world and a long-time editor of the journal HOMEOPATHY, freely admitted that homeopathy was unproven and its effects were most likely not due to any specific properties of the homeopathic remedies [which are, in fact, pure placebos] but largely rely on non-specific effects.

I agree with much that Campbell wrote but I disagree with one particular implication of his conclusions:Homeopathy has not been proved to work but neither has it been conclusively disproven….” and “…it is impossible to say categorically that all the remedies are without objective effect…”

This is an argument, we hear from proponents of alternative medicine with unfailing regularity:MY TREATMENT MAY NOT BE SUPPORTED BY GOOD SCIENCE [BECAUSE GOOD SCIENCE IS EXPENSIVE, AND WE CANNOT AFFORD IT] BUT IT HAS NOT BEEN DISPROVEN EITHER – AND, AS LONG AS IT IS NOT DISPROVEN, NOBODY SHOULD STOP US USING IT”

Campbell does not explicitly draw this latter conclusion but he certainly implies it. In his book, he explains that, even though homeopathic remedies probably are placebos, homeopathy does a lot of good through the placebo effect and through its spiritual aspects. And that is, in his view, sufficient reason to employ it for healing the sick. The very last sentence of his book reads: “Love it or loathe it, homeopathy is here to stay”

So the implication is there: alternative therapies can be as bizarre, nonsensical, implausible, unscientific or idiotic as they like, if we scientists cannot disprove them, they must be legitimate for general use. But there are, of course, two obvious errors in this line of reasoning:

  1. Why on earth should scientists waste their time and resources on testing notions which are clearly bonkers? It is hard to imagine research that is less fruitful than such an endeavour.
  2. Disproving homeopathy [or similarly ridiculous treatments] is a near impossibility. Proving a negative is rarely feasible in science.

In the best interest of patients, responsible health care has to follow an entirely different logic: we must consider any treatment to be unproven, while it is not supported with reasonably sound evidence for effectiveness; and in clinical routine, we employ mostly such treatments which are backed by sound evidence, and we avoid those that are unproven. In other words, whether homeopathy or any other medicine is unproven or disproven is of little practical consequence: we try not to use either category.

While I applaud Campbell’s candid judgement regarding the lack of effectiveness of homeopathic remedies, I feel the need to finish his conclusion for him giving it a dramatically different meaning: Homeopathy has not been proved to work but neither has it been conclusively disproven; this means that, until new evidence unambiguously demonstrates otherwise, we should classify homeopathy as ineffective – and this, of course, applies not just to homeopathy but to ALL unproven interventions.

‘Homeopathy in perspective’ is the title of a book by Anthony Campbell, the revised edition of which has recently become available. Dr Campbell has been a consultant at the Royal London Homeopathic Hospital (RLHH, as it was called then) for ~20 years and also served as the editor of the journal ‘Homeopathy‘ (as it is now called) for many years. He retired in 1998 but is still active in writing and teaching. His book is well-written, informative and far less promotional than one would expect. It summarizes the history of homeopathy in some detail and then discusses the scientific evidence – and it is, of course, this section that might be of particular interest for this blog and its readers.

I think Campbell is correct when he writes that it is wrong to say, as some critics do, that there is no objective evidence for homeopathy. There is, but most of it is of rather poor quality. Even at its best there is evidence for only a small effect, and when an effect is as small as this it may not be there at all. It is also disturbing that the better the quality of a trial the less likely it is to show a positive effect.

Amazing, coming from a retired consultant of the RLHH, isn’t it? It gets even more surprising as we read on: I conclude that there are no firm answers to questions about the efficacy of homeopathy to be found in the research that has been done up to now. Homeopathy has not been proved to work but neither has it been conclusively disproven – it is of course notoriously difficult to prove a negative.

A few paragraphs further on, Campbell provides his final conclusions on the evidence and gets even more explicit: My own assessment of homeopathy is that, while it is impossible to say categorically that all the remedies are without objective effect, any effect there may be is small and unimportant. The great majority, at least, of the improvement that patients experience is due to non-specific causes.

When I began saying and writing things like this, the world of homeopathy decided that I was a fraud and imposter who had no training in or knowledge of homeopathy; therefore, they almost unanimously agreed, my verdict was not to be trusted. I wonder how they are going to try to invalidate the words of someone who was for 20 years a consultant and director of the RLHH.

PS 

While I agree with much of what Campbell writes here, I have reservations about one particular aspect and will explain in the next post.

Dutch neurologists recently described the case of a 63-year-old female patient presented at their outpatient clinic with a five-week history of severe postural headache, tinnitus and nausea. The onset of these symptoms was concurrent with chiropractic manipulation of the cervical spine which she had tried because of cervical pain.

Cranial MRI showed findings characteristic for intracranial hypotension syndrome. Cervical MRI revealed a large posterior dural tear at the level of C1-2. Following unsuccessful conservative therapy, the patient underwent a lumbar epidural blood patch after which she recovered rapidly.

The authors conclude that manipulation of the cervical spine can cause a dural tear and subsequently an intracranial hypotension syndrome. Postural headaches directly after spinal manipulation should therefore be a reason to suspect this complication. If conservative management fails, an epidural blood patch may be performed.

Quite obviously, this is sound advice that can save lives. The trouble, however, is that the chiropractic profession is, by and large, still in denial. A recent systematic review by a chiropractor included eight cases of intracranial hypotension (IH) and concluded that case reports on IH and spinal manipulative therapy (SMT) have very limited clinical details and therefore cannot exclude other theories or plausible alternatives to explain the IH. To date, the evidence that cervical SMT is not a cause of IH is inconclusive. Further research is required before making any conclusions that cervical SMT is a cause of IH. Chiropractors and other health practitioners should be vigilant in recording established risk factors for IH in all cases. It is possible that the published cases of cervical SMT and IH may have missed important confounding risk factors (e.g. a new headache, or minor neck trauma in young or middle-aged adults).

Instead of distracting us from the fact that chiropractic can lead to serious adverse events, chiropractors would be well-advised to face the music, admit that their treatments are not risk-free and conduct rigorous research with a view of minimizing the harm.

The news that the use of Traditional Chinese Medicine (TCM) positively affects cancer survival might come as a surprise to many readers of this blog; but this is exactly what recent research has suggested. As it was published in one of the leading cancer journals, we should be able to trust the findings – or shouldn’t we?

The authors of this new study used the Taiwan National Health Insurance Research Database to conduct a retrospective population-based cohort study of patients with advanced breast cancer between 2001 and 2010. The patients were separated into TCM users and non-users, and the association between the use of TCM and patient survival was determined.

A total of 729 patients with advanced breast cancer receiving taxanes were included. Their mean age was 52.0 years; 115 patients were TCM users (15.8%) and 614 patients were TCM non-users. The mean follow-up was 2.8 years, with 277 deaths reported to occur during the 10-year period. Multivariate analysis demonstrated that, compared with non-users, the use of TCM was associated with a significantly decreased risk of all-cause mortality (adjusted hazards ratio [HR], 0.55 [95% confidence interval, 0.33-0.90] for TCM use of 30-180 days; adjusted HR, 0.46 [95% confidence interval, 0.27-0.78] for TCM use of > 180 days). Among the frequently used TCMs, those found to be most effective (lowest HRs) in reducing mortality were Bai Hua She She Cao, Ban Zhi Lian, and Huang Qi.

The authors of this paper are initially quite cautious and use adequate terminology when they write that TCM-use was associated with increased survival. But then they seem to get carried away by their enthusiasm and even name the TCM drugs which they thought were most effective in prolonging cancer survival. It is obvious that such causal extrapolations are well out of line with the evidence they produced (oh, how I wished that journal editors would finally wake up to such misleading language!) .

Of course, it is possible that some TCM drugs are effective cancer cures – but the data presented here certainly do NOT demonstrate anything like such an effect. And before such a far-reaching claim is being made, much more and much better research would be necessary.

The thing is, there are many alternative and plausible explanations for the observed phenomenon. For instance, it is conceivable that users and non-users of TCM in this study differed in many ways other than their medication, e.g. severity of cancer, adherence to conventional therapies, life-style, etc. And even if the researchers have used clever statistical methods to control for some of these variables, residual confounding can never be ruled out in such case-control studies.

Correlation is not causation, they say. Neglect of this elementary axiom makes for very poor science – in fact, it produces dangerous pseudoscience which could, like in the present case, lead a cancer patient straight up the garden path towards a premature death.

There is not a discussion about homeopathy where an apologist would eventually state: HOMEOPATHY CANNOT BE A PLACEBO, BECAUSE IT WORKS IN ANIMALS!!! Those who are not well-versed in this subject tend to be impressed, and the argument has won many consumers over to the dark side, I am sure. But is it really correct?

The short answer to this question is NO.

Pavlov discovered the phenomenon of ‘conditioning’ in animals, and ‘conditioning’ is considered to be a major part of the placebo-response. So, depending on the circumstances, animals do respond to placebo (my dog, for instance, used to go into a distinct depressive mood when he saw me packing a suitcase).

Then there is the fact that the animal’s response might be less important than the owner’s reaction to homeopathic treatment. This is particularly important with pets, of course. Homeopathy-believing pet owners might over-interpret the pet’s response and report that the homeopathic remedy has worked wonders when, in fact, it has made no difference.

Finally, there may be some situations where neither of the above two phenomena can play a decisive role. Homeopaths like to cite studies where entire herds of cows were treated homeopathically to prevent mastitis, a common problem in milk-cows. It is unlikely that conditioning or wishful thinking of the owner are decisive in such a study. Let’s see whether homeopathy-promoters will also be fond of this new study of exactly this subject.

New Zealand vets compared clinical and bacteriological cure rates of clinical mastitis following treatment with either antimicrobials or homeopathic preparations. They used 7 spring-calving herds from the Waikato region of New Zealand to source cases of clinical mastitis (n=263 glands) during the first 90 days following calving. Duplicate milk samples were collected for bacteriology from each clinically infected gland at diagnosis and 25 (SD 5.3) days after the initial treatment. Affected glands were treated with either an antimicrobial formulation or a homeopathic remedy. Generalised linear models with binomial error distribution and logit link were used to analyse the proportion of cows that presented clinical treatment cures and the proportion of glands that were classified as bacteriological cures, based on initial and post-treatment milk samples.

The results show that the mean cumulative incidence of clinical mastitis was 7% (range 2-13% across herds) of cows. Streptococcus uberis was the most common pathogen isolated from culture-positive samples from affected glands (140/209; 67%). The clinical cure rate was higher for cows treated with antimicrobials (107/113; 95%) than for cows treated with homeopathic remedies (72/114; 63%) (p<0.001) based on the observance of clinical signs following initial treatment. Across all pathogen types bacteriological cure rate at gland level was higher for those cows treated with antimicrobials (75/102; 74%) than for those treated with a homeopathic preparation (39/107; 36%) (p<0.001).

The authors conclude that homeopathic remedies had significantly lower clinical and bacteriological cure rates compared with antimicrobials when used to treat post-calving clinical mastitis where S. uberis was the most common pathogen. The proportion of cows that needed retreatment was significantly higher for the homeopathic treated cows. This, combined with lower bacteriological cure rates, has implications for duration of infection, individual cow somatic cell count, costs associated with treatment and animal welfare.

Yes, I know, this is just one single study, and we need to consider the totality of the reliable evidence. Currently, there are 203 clinical trials of homeopathic treatments of animals; and they are being reviewed at the very moment (unfortunately by a team that is not known for its objective stance on homeopathy). So, we will have to wait and see. When, in 1999, A. Vickers reviewed all per-clinical studies, including those on animals, he concluded that there is a lack of independent replication of any pre-clinical research in homoeopathy. In the few instances where a research team has set out to replicate the work of another, either the results were negative or the methodology was questionable.

All this is to say that, until truly convincing evidence to the contrary is available, the homeopaths’ argument ‘HOMEOPATHY CANNOT BE A PLACEBO, BECAUSE IT WORKS IN ANIMALS!!!’ is, in my view, as weak as the dilution of their remedies.

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