Posts Tagged Evidence Based Medicine

The Ethics of Homeopathy Jim McVeagh Apr 22


Dr Shaun Holt is no stranger to controversy, having last year laid into the Chiropractors. Now he, along with a number of other researchers, have written a letter to the New Zealand Medical Journal saying:

Practicing homeopathy or endorsing it by referring patients is not consistent with the ethical or regulatory requirements of practising medicine

This is unlikely to endear him to the many hundreds of GPs who use, or advocate the use of, homeopathic remedies! It certainly annoyed Susanna Shelton, co-president of the New Zealand Council of Homeopaths, who claims “homeopathy had been safely practised around the world for 200 years”. However, Shaun was not talking about the “safety” of homeopathy, but about the utility of it. If it does not work, it’s safety is a moot issue.

Shaun’s point is that it could be considered unethical to advocate a treatment that has no evidence backing it’s usefulness, particularly in the light of the Medical Council’s latest directive on alternative therapies which clearly states:

Doctors must inform patients on the nature of alternative treatments they offered, the extent to which they were consistent with conventional theories of medicine, whether they had the support of the majority of doctors, and their likely effectiveness according to peer-reviewed medical publications.

Unfortunately for proponents of homeopathy, a recent review of all the Cochrane evidenced-based reviews on homeopathy was less than enthusiastic. The article (found here) concludes:

The most reliable evidence – that produced by Cochrane reviews – fails to demonstrate that homeopathic medicines have effects beyond placebo.

Indeed, a quick trip through some of the latest issues of reputable journals such as Homeopathy, Journal of Alternative and Complementary Medicine and Evidenced Based Complementary and Alternative Medicine, reveals much waffle and little in the way of real science. Even the odd randomised trials are usually poorly done and use very small numbers of patients. The larger, better done trials invariably fail to show significant results. All in all, it is hard not to draw the conclusion that homeopathy is dependent chiefly upon the placebo effect.

Readers of this blog will know that I have a soft spot for the placebo effect. I believe it can be a very useful tool in medicine, provided that the doctor/patient relationship is robust enough to survive the eventual discovery that the medication is question is bogus. However, the basic problem with homeopathy is that it is all bogus and the placebo effect cannot be used blindly with every patient but has to be used sparingly and carefully when appropriate. I therefore tend to agree with Shaun that it is difficult to approve of the wholesale use of homeopathy in a doctor’s practice.

Supporters of homeopathy usually point out that it is harmless and relatively cheap and that it does have anecdotal benefits, though it is usually uncertain whether these benefits are derived from the holistic and detailed manner of the consultation or the “medicine” itself. Unfortunately, homeopathy has a number of undesirable effects that far outweigh its nebulous gains.

  • There is a substantial risk that patients may not seek conventional care in life or limb threatening situations. Shaun makes this very point in the Herald article. The situation is made more dangerous by the fact that homeopathy practitioners have a distinct aversion to “allopathic” medicine and tend to avoid referring back to conventional doctors.
  • Scarce resources are wasted on homeopathy. While the first point is well-known, it is not really appreciated that valuable resources are being wasted in terms of doctor’s time, patient’s money and manufacturing equipment, to name a few. This is not as acute a problem in New Zealand (where few public health resources are spent on homeopathy) as it is in the US, where there are entire hospitals and clinics dedicated to the subject.
  • Support for science-based medicine is weakened. It is quite likely that some commentators will get quite hot under the collar telling me all the faults of conventional medicine. Some of these criticisms may be justified but a great many will be based on an antipathy toward scientific medicine that is wholly unjustified. The vaccine debate would be an excellent example of this effect, but homeopathy provides good fodder for some of the more flakey responses to medicine.
  • Support for genuine complementary therapies may be weakened. There are some alternative therapies such as acupuncture and meditation, that produce verifiable, evidence-based results. Yet these therapies run the risk of being dismissed by doctors and patients being bombarded by ludicrous claims from myriad other complimentary “therapies”, including Homeopathy. (source: Smith K. Against Homeopathy – A Utilitarian Perspective. Bioethics – epub)

The conclusion is therefore inescapable that homeopathy is not a harmless thing that slightly flakey patients go for. It is not a valid therapeutic modality that doctors can use. It is a deeply anti-scientific subject of dubious merit that subtly undermines every that medicine stands for. Doctors who use it should seriously consider the ethics of their stance.

PS: You can find a poster size version of the wonderfully rude graphic right here.


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Newsflash! Advertisers Lie! Jim McVeagh Feb 28

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Yes, I know it is almost impossible to fathom such depravity, but some pharmaceutical advertisers make unsubstantiated claims in medical journals! (/SARCASM OFF) Such is the conclusion of Ben Goldacre of the Guardian, writing on the Bad Science Blog. Goldacre is writing about a recent research article in the Netherlands Journal of Medicine “Are claims of advertisements in medical journals supported by RCTs?“. The article comes to the conclusion that only 40% of the adverts quoted a high-quality RCT (Randomised Control Trial) that actually supported the claims made in the advert (some trials were high quality but did not support the claims). Scarily, only 17% of the claims were supported by a relevant, good quality RCT that was not sponsored by the pharmaceutical company.

The study had 250 medical students go through 158 RCTs from 94 advertisements using a modified version of the Chalmers’ score. Why medical students? Goldacre suggests amusingly that they are cheap! But the real reason is that the students had just completed the section of their study that deals with appraising evidence-based medicine. They were therefore about as able to judge the trials as an average GP, perhaps more so. They were given an objective scoring system to follow and they had no previous exposure to prescribing the drugs being advertised. This would have given an accurate, unbiased assessment of the worth of these trials without resorting to the use of statisticians or academics. This gives a good “real world” picture of the value of these trials, should a GP or hospital doctor have asked for them.

It comes as no real surprise that so few of the advertisements had decent clinical data to back them up. This has been a common finding in many studies including this large swiss study of 2068 adverts. Goldacre cites this excellent meta-analysis of 24 studies on this subject from the open access journal Plos One. Even as far back as 1992, the highly regarded Annals of Internal Medicine published this study whose conclusions included:

In 44% of cases, reviewers felt that the advertisement would lead to improper prescribing if a physician had no other information about the drug other than that contained in the advertisement.

The moral of the story being that when the drug rep or an advert makes a claim, always insist on reading the cited study. I have done this from the time of my graduation, nearly thirty years ago, and my impression is much the same as these studies. About half of the claims made by reps are verifiable. To be fair on the drug reps, most of them do not know how to judge a study and are just going by what they have been told. And they are almost always perfectly willing to find you a copy of the paper.

From an ethical point of view, I cannot see how any doctor could change his prescribing habits without at least assessing the claims made by pharmaceutical companies, formally. I know many of my colleagues take the recommendations of the specialists they use, relying on their judgement as to the worth of the product. I think this is not an unreasonable thing to do, as most specialists are more able to assess these claims than the average GP. However, I still make it a policy to assess papers myself, as even my specialist colleagues may not be immune to the lure of the shiny new pill on the market.

So what makes a paper a bad one? Essentially, bias in selection, lack of controls and low numbers. The first two are quite easy to spot once you know a little about the subject, the last is the commonest reason for considering a trial dubious. I can’t tell you how many times I have seen adverts claiming a great “P” value of 0.001 (That’s Probability, not Methamphetamine, BTW – anything less than 0.05 suggests that this is not a random chance). When you ask how many were in the study, you keep getting answers like 30 or 50. This means that it is dangerously likely that the result may simply be a type 1 error (the small sample has accidentally been taken from an abnormal part of the population – giving a spuriously significant result). This is a particular problem in medical trials. This is not to say that small trials are not worth doing, but that the result should always be treated with caution. Multiple small trials with the same result are much more reassuring, as is a large trial with a similar result.

Clearly adverts effect the way doctors prescribe drugs, otherwise drug companies would not run them. This is worrying considering that half of the claims made are either unverified or blatantly false. Prescribing medicine should be done on a purely evidence-driven basis. Prescriptions based on what pharmaceutical companies want you to believe, leave doctors open to charges that there is no more scientific basis to conventional medicine than to something like homeopathy. Worse, it could seriously disservice a patient, all in the name of the pharmaceutical company making another buck.

Doctors owe it to their patients to check out pharmaceutical company claims in full. It is stupid to accept the word of a person who has a vested financial interest in his product and it is nonsense to get our medical knowledge from the glossy brochures of drug reps.

Hat Tip:  David Whyte


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