Posted by: colinhockings
If you’re a skeptic, particularly if you’re interested in the fight against pseudoscience and fuzzy logic in health care, Edzard Ernst is a man you should listen to closely. And if the name rings a faint bell you’ve probably heard of him as the co-author of ‘Trick or Treatment? Alternative Medicine on Trial‘ with Simon Singh. While there are hundreds of skeptical bloggers making a lot of noise about alternative medicine, Edzard Ernst’s full time job is to do it properly. With his group at the Peninsula Medical School (at the Universities of Exeter and Plymouth) he writes systematic reviews and meta-analyses of complementary medicine, as well as carrying out clinical trials (although apparently it’s been a while due to budget constraints) and writing books and articles for various newspapers. In short, he’s a very busy man, doing lots of important work – he’s published over 700 articles in peer-reviewed scientific journals!
In the last few weeks Edzard Ernst published two systematic reviews, one examining the utility of chiropractic spinal manipulation for asthma in children, and the other on chiropractic spinal manipulation for infantile colic. Those of you who are familiar with the ongoing trial of Simon Singh at the hands of the British Chiropractic Association will understand the significance. In short: Simon Singh is being sued because he pointed out that there was no evidence that chiropractic could help children with asthma or colic – among other pediatric complaints – and that the BCA promote it’s use for these conditions anyway.
I’ll give a quick summary of the two studies but I recommend reading them yourself (if you have access to the journals) because they are so short.
‘Spinal manipulation for asthma: A systematic review of randomised clinical trials’
They looked for every relevant study they could find on several databases as well as hand-searching references: a total of 35. Then they took out all the studies that weren’t randomised, didn’t study human patients (of any age), didn’t study chiropractic spinal manipulation (as opposed to other auxiliary treatments that are performed by chiropractors, or spinal manipulations performed by other professionals such as osteopaths), and didn’t study a clinical outcome. These criteria seem quite reasonable to me, but despite the bar being set so low only three studies were usable. Two of the studies concluded that there was no effect, and the third did not compare the control group with the experimental group ‘because of the high risk of committing type I and type II errors’. I don’t quite know if that is sufficient justification to avoid what most would consider the entire point of the experiment, but apparently they claimed to be a preliminary trial to determine the feasibility of a larger study. They did, however, deign to say that there was ‘little or no change’ between the patients before and after the manipulation.
Professor Ernst went on to say that the review wasn’t powerful enough (read: there aren’t enough strong studies) to prove chiropractic as being ineffective, but ’science in general and the RCT [Randomised Clinical Trial] in particular are not good tools for proving a negative’. Thus, and I think this is a very important point that applies to all claims by alternative medicine enthusiasts:
“[It is] the responsibility of those who claim spinal manipulation to be effective to demonstrate this beyond reasonable doubt. In the absence of such proof, any claim that spinal manipulation (or indeed any other therapy) is effective seems unjustified and irresponsible”
‘Chiropractic spinal manipulation for infant colic: a systematic review of randomised clinical trials’
This study was performed in much the same way as the other, however the trials that were considered to be of sufficient quality (3 out of 52) were still fairly poor, with low sample sizes and insufficient controls, as well as rubbish measures of outcome. Thus the conclusions that can be drawn are correspondingly shakier. The two slightly better trials reported no significant differences between the groups, and the methodology of the third trial, which reported a small change, was pretty dire to say the least. They didn’t report on the recruiting process, so it presumably consisted of asking parents to join a trial of chiropractic (and so probably selecting parents who believe that chiropractic will work), then they didn’t blind the parents as to whether or not their child had recieved chiropractic manipulation or a placebo drug, and then they relied solely on the parents evaluation of severity.
Colic is particularly interesting with regard to alternative medicine because we have very little idea about what causes it and no real idea about how to treat it. This sets the stage for lots of worried parents feeling powerless to help their children who are wracked with inconsolable crying, flushed faces, flatulence and ‘meteorism’ (drawing up their legs). The kicker is that it usually resolves spontaneously. It is easy to imagine parents who go their pediatrician being told not to worry, to just sit tight and wait, and when the disease has gone on for long enough they start hunting for alternative ‘remedies’ (here’s your regression to the mean). They may try a few different things and suddenly their child gets better. If I was an evil businessman representing chiropractic I would want to make sure that lots of parents come to see me for their baby’s colic because they’ll probably be converts for life once the child gets better on its own. To give you an idea of the magnitude of this effect, one retrospective study reported that 91% of colic patients showed a positive response to chiropractic.
One final note about these systematic reviews: anyone who would dismiss them as being written by Simon Singh’s friend to stack the evidence against the BCA has a tough case to argue. The point of a systematic review (as opposed to a run-of-the-mill, garden variety review) is to look at all the evidence on a certain topic, and evaluate it according to pre-defined criteria. In addition, the data-extraction and Jadad scoring (an assessment of the methodological quality) were performed by two independent reviewers.
Also highly recommended: Edzard Ernst published one of the best take-downs of the BCA ‘plethora of evidence’ in the BMJ a few months ago.
Ernst E (2009). Spinal manipulation for asthma: A systematic review of randomised clinical trials. Respiratory medicine PMID: 19646855
Ernst E (2009). Chiropractic spinal manipulation for infant colic: a systematic review of randomised clinical trials. International journal of clinical practice, 63 (9), 1351-3 PMID: 19691620
—— Update ——
This post was chosen as an Editor’s Selection for ResearchBlogging.org