Did we not have a flurry of systematic reviews of homeopathy in recent months?
And were they not a great disappointment to homeopaths and their patients?
Just as we thought that this is more than enough evidence to show that homeopathy is not effective, here comes another one.
This new review evaluated RCTs of non-individualised homeopathic treatment (NIHT) in which the control group received treatments other than placebo (OTP). Specifically, its aim was to determine the comparative effectiveness of NIHT on health-related outcomes for any given condition.
For each eligible trial, published in the peer-reviewed literature up to the end of 2016, the authors assessed its risk of bias (internal validity) using the seven-domain Cochrane tool, and its relative pragmatic or explanatory attitude (external validity) using the 10-domain PRECIS tool. The researchers grouped RCTs by whether these examined homeopathy as an alternative treatment (study design 1a), adjunctively with another intervention (design 1b), or compared with no intervention (design 2). RCTs were sub-categorised as superiority trials or equivalence/non-inferiority trials. For each RCT, a single ‘main outcome measure’ was selected to use in meta-analysis.
Seventeen RCTs, representing 15 different medical conditions, were eligible for inclusion. Three of the trials were more pragmatic than explanatory, two were more explanatory than pragmatic, and 12 were equally pragmatic and explanatory. Fourteen trials were rated ‘high risk of bias’ overall; the other three trials were rated ‘uncertain risk of bias’ overall. Ten trials had data that were extractable for meta-analysis. Significant heterogeneity undermined the planned meta-analyses or their meaningful interpretation. For the three equivalence or non-inferiority trials with extractable data, the small, non-significant, pooled effect size was consistent with a conclusion that NIHT did not differ from treatment by a comparator (Ginkgo biloba or betahistine) for vertigo or (cromolyn sodium) for seasonal allergic rhinitis.
The authors concluded that the current data preclude a decisive conclusion about the comparative effectiveness of NIHT. Generalisability of findings is restricted by the limited external validity identified overall. The highest intrinsic quality was observed in the equivalence and non-inferiority trials of NIHT.
I do admire the authors’ tenacity in meta-analysing homeopathy trials and empathise with their sadness of the multitude of negative results they thus have to publish. However, I do disagree with their conclusions. In my view, at least two firm conclusions ARE possible:
- This dataset confirms yet again that the methodological quality of homeopathy trials is lousy.
- The totality of the trial evidence analysed here fails to show that non-individualised homeopathy is effective.
In case you wonder why the authors are not more outspoken about their own findings, perhaps you need to read their statement of conflicts of interest:
Authors RTM, YYYF, PV and AKLT are (or were) associated with a homeopathy organisation whose significant aim is to clarify and extend an evidence base in homeopathy. RTM holds an independent research consultancy contract with the Deutsche Homöopathie-Union, Karlsruhe, Germany. YYYF and AKLT belong to Living Homeopathy Ltd., which has contributed funding to some (but not this current) HRI project work. RTM and PV have no other relationships or activities that could appear to have influenced the submitted work. JRTD had no support from any organisation for the submitted work; in the last 3 years, and for activities outside the submitted study, he received personal fees, royalties or out-of-pocket expenses for advisory work, invitational lectures, use of rating scales, published book chapters or committee membership; he receives royalties from Springer Publishing Company for his book, A Century of Homeopaths: Their Influence on Medicine and Health. JTRD has no other relationships or activities that could appear to have influenced the submitted study.
If one had wanted to add insult to injury, one could have added that, if, despite such conflicts of interest, the overall result of this new review turned out to be not positive, the evidence must be truly negative.