Tuesday, 7 April 2009

Over the Hills and far, far away

Have a look at these quotes from a recent trial of homeopathy in dogs and try to guess which journal they have come from.
We have all the usual tactics and excuses:

1/ Cherry picking of data: “To date, comprehensive meta-analyses of placebo-controlled trials in human medicine have, in general, suggested that homeopathy is superior to placebo"
2/ Homeopathy is too sophisticated to be assayed by mere science: “One obstacle to the performance of clinical trials to investigate veterinary homeopathy is the holistic approach taken by homeopathic practitioners, in which the whole patient is treated on the basis of the individual signs and constitutional characteristics, rather than just a specific disease.
3/ Any study which suggests homeopathy is anything less than completely effective is plainly wrong: “... a previous single-blinded, placebo-controlled study was conducted... to determine the efficacy of a commercial homeopathic remedy in the treatment of canine atopic dermatitis. Although no beneficial effects were seen, the study design was widely criticised by homeopathic practitioners who wrote to the journal in which the study was reported, claiming that the requirement for individualisation of remedies had been completely misunderstood and ignored by the authors...”
4/ There’s no such thing as real medicine, it’s just homeopathy’s evil twin, “allopathy”: “a novel, two-stage study design was tested in order to allow adherence to both homeopathic and allopathic principles.”
5/ Anyone who doesn’t believe in homeopathy is an idiot: “Conventional clinicians who are sceptical about homeopathy might interpret the results differently, and attribute the responses to chance and ‘wishful thinking’ on behalf of the owners."
6/ Anyone who doesn’t believe in homeopathy is a complete idiot: “... the chances of a sudden resolution occurring coincidentally after the remedies had been administered would be small.”
... and finally,
7/ Bugger the results, that’s not what we want to hear, let’s hear some heart-warming anecdotes instead: “The owners of the five dogs were in no doubt that the improvements seen in their dogs’ signs were a result of the homeopathic remedies.

Well, despite what you may think from the quotes they’re not from some partisan, pro-homeopathic journal which treats magic on a par with science. Sadly for the veterinary profession it’s from our dearly beloved premier journal, The Veterinary Record. To be precise, Hill, P. B., Hoare, J., Lau-Gillard, P., Rybnicek, J., and Mathie, R.T. Pilot study of the effect of individualised homeopathy on the pruritis associated with atopic dermatitis in dogs, Veterinary Record 164:364-370

This paper was designed as a pilot study of homeopathy as a treatment for pruritis (itching) in dogs suffering from allergic skin disease. To give you a bit of background, this condition, known as atopy, is a terrible one which causes an irresistible compulsion on the part of the suffering dog to continuously itch and scratch itself so badly that sometimes its skin ends up looking like raw meat and oozes blood and serum. It is caused by an allergy to inhaled substances such as pollen, house-dust mites and fungal spores and there is no cure. In the early stages is starts insidiously, often only obvious at a certain time of year, it is what is described as “seasonal”, so it is worse when, say, the pollen of a particular plant is plentiful in the environment. Later on, as the dog grows older the season lasts longer and longer until the affliction appears almost permanent. Nevertheless it is still prone to periods of waxing and waning; it’s not equally as bad all the time. For whatever reason there are good periods and bad periods which result in the condition ameliorating for variable lengths of time, up to several weeks or months. Environmental conditions such as a cool spell, changes in diet, routine or even washing powder will all impact on the severity and conspire to change its presentation at different times.

In this trial the authors took twenty dogs suffering from atopy and put them on homeopathy for a while. After a while five of them improved (or, rather, as the authors chose to describe it, “responded”). Now normally, at this point many trials would have had a placebo group, which is to say a similar group of dogs who were given identical looking blank tablets to see if they responded any differently. This allows the authors to compare the numbers of dogs who might have improved for any reason other than homeopathy with the numbers who improved in the group actually having the homeopathy. In this case though the design of the test didn’t include a placebo group so we are left guessing how many of the subjects would have improved anyway, regardless of treatment. In fact in this pilot stage of the trial all the owners knew that they were giving homeopathy to their dogs.

Once the pilot stage was over the five dogs which had improved were put forward to the next stage, a blinded trial (where owners wouldn’t know whether they were giving homeopathy or a blank placebo). Before this was started however one of the dogs’ symptoms improved so much it couldn’t participate and sadly, one of them was put to sleep as a result of epilepsy. So that left the authors with three dogs out of a total of twenty to do the most important phase of the trial. Now I’m not the world’s greatest statistician but even I can tell that any trial involving three participants is not going to be worth the paper it is written on. Much, much larger numbers are needed to show any sort of effect, especially when most previous homeopathic trials of any quality have been unable to distinguish homeopathy from placebo. If the difference is so small (some would say non-existent) you have to work very hard to test it and a trial involving three dogs is no where near the mark. OK, it might have made an interesting letter but a six page paper in the UK’s top Veterinary Journal; I don’t think so.

The tone of the paper is strange and rather out of keeping with the usual detached language of such works. The authors seem to embrace, without question, the language and assumptions of homeopathy. It reads exactly the same way that one would expect a paper in a homeopathic journal to sound. There is an enormous section on homeopathic type signs (or “rubrics” as they’re called in homeo-speak) - one dog is described as ‘clairvoyant’, another is described as suffering from ‘vaccinosis’ (a condition entirely fabricated by purveyors of alternative medicine with no place in a scientific journal), yet another has an ‘aversion to onions’ while another is ‘very jealous but does not console owner’. All these descriptions are given straight-faced without rationale or explanation as to their significance or bearing on atopy. At a point sometime after the trial the authors, perhaps unhappy with homeopathy’s poor showing, decided to telephone the owners of one of the dogs from the first phase of the trial and ask how things were progressing. Even though this dog did not improve well enough to meet the study’s criteria for inclusion in the blinded phase the authors, for reasons known only to themselves, deemed it necessary to discuss the fact that the owner felt there had, after all, been a good ‘response’ and actually the dog had also ‘responded’ to some more homeopathy (nothing to do with the trial) six months later - well big deal!

The conclusion is awash with contradictions, almost as if several contributors have been working on different sections independently of one another. There is this statement of fact, “The success rate was lower than the 60 to 70 per cent predicted by the homeopath at the outset of the study”. Fair enough you might think, but it is immediately followed by a whole list of excuses as if the authors already know homeopathy works, but here are the reasons it didn’t in this case. Then, incredibly, we are told, “the authors consider that the overall success or failure rate in this study is somewhat irrelevant” Well, this trial certainly didn’t demonstrate any success for homeopathy so they must mean that failure is irrelevant - so why bother to do the trial if the outcome didn’t matter?

Despite the incredibly low power of the trial the authors actually claim, with no justification, to have shown that “even with a cautious interpretation” the results support the view that homeopathic remedies are beneficial in treating atopy (this is from three dogs remember). Then, a few lines further on, the whole piece finishes with the non-sequitur last line, “There is no justification for using the findings reported here to substantiate or repudiate the overall efficacy of homeopathy in either veterinary or human medicine”.

All very strange and, I fear, a sad day for our profession.


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