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Bandolier's law of inverse claims (Editorial)


Bandolier may be getting old and crotchety, but, increasingly, being told the obvious raises the blood pressure. That, perhaps, reflects the fact that we know that there is so much we don't know, or don't know well enough, that telling people the obvious seems a real waste of time.

Here's a good one for you, from a recent issue of JAMA. It is a paper [1] on factors associated with deaths and injuries from hot-air balloon crashes. The paper says that "in univariate analysis, collision with the ground was the most significant predictor of fatality or serious injury (P<0.01)."

Well, fancy that! Most Bandolier readers would have predicted this result. What, though, about those things that are unprovable, or for which there is no proof, so many of which seem to appear round the fringes of healthcare?

Bandolier's law of inverse claims

A quick screening test to determine whether or not to read about a new product or service is offered by this law. It states that the more benefits claimed for a product, the less likely any of them are to be true. Take, as an example, an E-mail received for Ericson's Alkali-Mine Coral calcium from Okinawa. The E-blurb states that "over 150 diseases are linked to ionic calcium deficiency", and that "reports from users" show "total or partial relief from symptoms of"...... The list starts with arthritis and goes on to include athlete's foot and most other ailments.

Messenger not the message

Then look at a chap called Andrew Weil, who made the cover of Time Magazine as a "Medicine Man" [2]. Much more difficult this, as Dr Weil advises lots of good things - eating sensibly, walking, making time for relaxation, avoiding coffee, losing weight. He also advises using herbal remedies - and we know that some, like St John's Wort and Gingko do indeed work.

Here it is the packaging that is important. The same message about exercise, diet, and lifestyle change probably plays less well in Scunthorpe on a wet Tuesday in January. So you will not be surprised to hear that Dr Weil practises in Arizona.

Debunking the absurd

Imagine for a moment that Bandolier 's editor comes up to you (or, worse, a sick patient) and says that he can see that your aura is disturbed. He then says that for a small fee, and without even touching you, he can put it right so that you will be more in balance with yourself. Money passes in one direction, and hands are waved airily in the other, and the transaction is complete. This technique of "therapeutic touch" is claimed to do things from helping children make sense of the world to helping to bring some dead back to life [3].

Therapeutic touch has been debunked in a superb paper in JAMA [3]. There are three good things about this paper. One is the background explanation of the "theory" behind the practice, another is the systematic review of the literature which shows that "at most only 1 of the 83 {studies} may have demonstrated independent confirmation of any positive study", and the third is a terrific randomised study by a nine year old girl showing that the practitioners cannot substantiate their claims.

In the RCT, 21 practitioners were challenged to "sense the aura" from the girl's hand. They sat with hands extended through a screen with palms up. The girl tossed a coin to determine which hand was going to be tested, then put her hand 5-10 centimetres above one of the practitioner's.

All practitioners were confident or very confident that they could pass the test with flying colours. By chance they should have guessed 50% correctly. They actually averaged 47% (Figure).

To do significantly better than chance they had to be right at least 8 of 10 times. Only one ever achieved this, then fell back to chance on re-test.

Warp and weft

Process and outcome are interwoven like warp and weft. We may be sceptical about the benefits of interventions that promise relief for 100 diseases, but many people are impressed by these claims and the confident style in which they are made. Sales of vitamins and other health store products are booming in Western countries.

Avoid fuzzy thinking

In making evidence-based decisions we have to be more sceptical. If there is no proof that an intervention works, then the norm should be that it is not used. Claims that it does no harm should be treated with healthy scepticism. Adverse effects of treatments that do much good are treated with proper seriousness - oral contraceptives and rare thrombosis as one example. If we don't know that something works, the chances of knowing that is does not do harm are small.

Indeed, it is worse than that. The logic, surely, is this: if we don't know that an intervention does any good, and we don't know that the intervention doesn't do any harm, then the only course of action open to us is not to use it until it is at least proven to be safe.

Where an unconventional approach can be shown to work, then we have to treat those claims with appropriate seriousness. Many herbal remedies are effective, for instance and another example later in this issue is a systematic review of homeopathic interventions which show positive effects after abdominal surgery. Healthy scepticism should not include a closed mind.

References:

  1. CT Cowl, MP Jones, CF Lynch et al. Factors associated with fatalities and injuries from hot-air balloon crashes. JAMA 1998 279, 1011-4.
  2. J Kluger. Mr Natural. Time 1997 May 19, 44-51.
  3. L Rosa, E Rosa, L Sarner. A close look at therapeutic touch. JAMA 1998 279:1005-10.



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