A review published in The Lancet which claimed that homeopathy is just a placebo, has been slammed as seriously flawed in two separate studies.
Back in August 2005 an editorial in the Lancet entitled 'The End of Homeopathy', prompted by a review comparing clinical trials of homeopathy with trials of conventional medicine claimed that homeopathic medicines are just placebo.
The review was based on 6 clinical trials of conventional medicine and 8 studies of homeopathy but did not reveal the identity of these trials and has been criticised for its opacity as it gave no indication of which trials were analysed and the various assumptions made about the data.
Sufficient detail to enable a reconstruction was eventually published and two recently published scientific papers based on such a reconstruction challenge the Lancet review.
George Lewith, Professor of Health Research at Southampton University says the review gave no indication of which trials were analysed nor of the various vital assumptions made about the data which is not usual scientific practice.
He says if it is presumed that homeopathy works for some conditions but not others, or changes the definition of a 'larger trial', the conclusions change and this indicates a fundamental weakness in the conclusions - and they are not reliable.
Professor Lewith says as analysis of all high quality trials of homeopathy yields a positive conclusion - the 8 larger higher quality trials of homeopathy were all for different conditions; if homeopathy works for some of these but not others the result changes, implying that it is not placebo and the comparison with conventional medicine was meaningless and doubts still remain about the unpublished criteria used in the review, including the definition of 'higher quality'.
The Lancet review was led by Prof Matthias Egger of the Department of Social and Preventive Medicine at the University of Berne, and started with 110 matched clinical trials of homeopathy and conventional medicine, these were reduced to 'higher quality trials' and then to 8 and 6 respectively 'larger higher quality trials'.
Based on these 14 studies the review concluded that there is 'weak evidence for a specific effect of homoeopathic remedies, but strong evidence for specific effects of conventional interventions'.
As there are a limited number of homeopathic studies it is quite possible to interpret these data selectively and unfavourably, which is what appears to have been done in the Lancet review.
Professor Lewith says this casts serious doubts on the review, showing that it was based on a series of hidden judgments unfavourable to homeopathy and an open assessment of the current evidence suggests that homeopathy is probably effective for a number of conditions including allergies, upper respiratory tract infections and 'flu, but more research is desperately needed.