Posted by apgaylard on January 25, 2008
It’s not just bad clinical CAM trials that can mislead; it’s also the positive spin put on good ones with negative outcomes.
In some recent correspondence R. Barker Bausell, author of the compelling “Snake Oil Science – The Truth About Complementary and Alternative Medicine“, provides an instructive example.
It’s a bit of a retrospective: this study and the resulting slew of poor press coverage was commented on by David Colquhoun and Ben Goldacre, among others, last year. Nevertheless, I think that Baussell’s observations are well worth considering; so I have provided them below.
“[…]Instead, let me give you an example of a disingenuous interpretation of a good CAM trial. This one was published in the September 24th issue of the Archives of Internal Medicine entitled “German Acupuncture Trials (GERAC) for Chronic Low Back Pain.” The trial in question involved both an apparently well conceived placebo control (extremely shallow insertion of needles at meridian irrelevant points) along with a second control group involving conventional medical treatment for chronic back pain.
The results themselves were quite clear cut and expected. Whenever a CAM therapy is compared to a credible placebo control there is practically never any difference between the two groups because CAM therapies have no real biological mechanism; they appear to be only capable of eliciting placebo effects. Also, whenever a CAM therapy and a credible placebo are compared to conventional medical treatment, then both the CAM and the placebo groups will elicit a greater placebo effect than this second control group. The reason for this is also straightforward: patients who sign up to participate in a CAM trial do so because they expect the CAM therapy to benefit them. This means that if they think they are receiving what they volunteered for in the first place, they will be the recipient of a bigger placebo effect.
But in published CAM trials, the Devil is not so much in the details but how they are interpreted. Thus after noting that there was no difference between true and sham acupuncture, the authors began talking about their acupuncture groups and how they were both superior to conventional therapy and how, since the position or even the depth of the needle insertions didn’t seem to matter, there must be something very, very special about acupuncture that hadn’t yet been discovered.
Now of course from the perspective of simple logic, this is equivalent to a pharmaceutical company, after having sponsored a placebo controlled trial and finding no difference between their drug and its placebo, petitioning the FDA to grant them permission to market both – after all the placebo was carefully modeled to be as similar to their drug as possible: looking, tasting, and smelling almost identically to it. There must be, this logic would suggest, something very, very special about their drug even though its specific ingredients may not be as important as originally assumed. This, I hold, is disingenuous nonsense.”
If you are tempted to think that not many would fall for this sort of nonsense, think again. The NHS’ National Library for Health “Complementary and Alternative Medicine Specialist Library” carries an article called “Acupuncture for low back pain” which was published as part of “National Knowledge Week on CAM for Low Back Pain 2007“. It made contains this ludicrous interpretation of the study:
“[…]The GERAC (German Acupuncture trial) trial on low back pain (n=1162; results not yet published in English) found acupuncture to be superior to guideline-based standard treatment, though not superior to minimal (superficial non-point) acupuncture. On the basis of this, the German health authorities have decided that acupuncture will be included in routine reimbursement by social health insurance funds for the treatment of low back pain[…]”
So, not only did CAM advocates fall over themselves to misinterpret this trial, now it seems that the German tax payer will have to foot the bill. With this sort of disingenuous nonsense pervading the NHS’ CAM ‘evidence’ base the situation in the UK may well be as bad.
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