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A meta-analysis is a means of combining results from more than one trial to look for overall trends. (NB! In general complicated research terminology such as OR, CI, and words such as significant or randomized should only be used in communications with people who will understand such terminology. Otherwise stick to what can be understood by all, e.g. a survey of all the high quality research that has been carried out clearly shows that homeopathy is effective.)
Results were found in favour of homeopathy in 20 of 22 systematic reviews on the effect of homeopathic high-potencies on cells or living organisms. For upper respiratory tract infections and allergies six out of seven studies were in favour of homeopathy. The authors of this article concluded that the effectiveness of homeopathy can be supported by clinical evidence and treatment is safe.
The article has been published by authors who took part of the Program for Evaluation of Complementary Medicine (PEK), the same program which in August 2005 resulted in the publication of an article by Shang et al, where the conclusion was that the effect of homeopathy is placebo. Bornhöft et al. Effectiveness, Safety and Cost-Effectiveness of Homeopathy in General Practice – Summarized Health Technology Assessment. Forsch Komplementärmed 2006;13(suppl 2):19-29.
In a review of homeopathy research the authors found three independent systematic reviews of placebo-controlled trials on homeopathy that reported effects that seem to be more than placebo, and one review that found its effects consistent with placebo. Jonas, W. B., Kaptchuk, T. J., & Linde, K. 2003b, "A critical overview of homeopathy", Ann.Intern.Med., vol. 138, no. 5, pp. 393-399.
A systematic review and meta-analysis showed highly significant results for surveys adding up to a total of 2 617 patients (P=0.000036). Results were not that significant for high quality surveys (P=0.08). The author concludes that further high quality studies are needed to confirm results. Cucherat, M., Haugh, M. C., Gooch, M., & Boissel, J. P. 2000, "Evidence of clinical efficacy of homeopathy. A meta-analysis of clinical trials. HMRAG. Homeopathic Medicines Research Advisory Group", Eur.J.Clin.Pharmacol., vol.. 56, no. 1, pp. 27-33.
A systematic review of results from 93 substantive RCTs was carried out by Robert Mathie (2003). It concludes that of the 35 different medical conditions covered by these trials the weight of evidence favours a positive treatment effect in 8: childhood diarrhoea, fibrositosis, hay fever, influenza, pain (miscellaneous), side-effects of chemotherapy or radiotherapy, sprains and upper-respiratory tract infections. Mathie, R. The research evidence base for homeopathy: a fresh assessment of the literature. Homeopathy 92: 84-91. 2003.
Meta-analysis of 89 trials of homeopathic medicine versus placebo. Result: significantly in favour of homeopathy (OR 2,45 (95% CI 2,05-2,93)). This meta-analysis included 186 placebo-controlled studies of homeopathy published until mid-1996, of which data for analysis could be extracted from 89. The overall odds ratio was 2.45 (95% confidence intervals 2.05-2.93) in favour of homeopathy, which means that the chances that homeopathy would benefit the patient were 2.45 times greater than placebo. When considering just those trials of high quality published in MEDLINE listed journals, and with predefined primary outcome measures, the pooled odds ratio was 1.97 and significant. Even after correction for publication bias the results remained significant. The main conclusion was that the results "were not compatible with the hypothesis that the effects of homeopathy are completely due to placebo". If the result of new trials were to show no difference between homeopathy and placebo, we would have to add 923 trials with no effect with 118 patients in each in order to balance the two. Linde K, Clausius N, Ramirez G, et al. Are the clinical effects of homoeopathy placebo effects? A meta-analysis of placebo-controlled trials. Lancet 1997;350:834-43
HMRG report with overview of clinical research in homeopathy, identified 184 controlled clinical trials. They selected the highest quality randomized control trials, which included a total of 2617 patients for a meta-analysis. This meta-analysis resulted in a p-value of 0.000036 (which means that results are highly significant) indicating that homeopathy is more effective than placebo. The researchers concluded that the "hypothesis that homeopathy has no effect can be rejected with certainty". Homeopathic Medicine Research Group. Report to the European Commission directorate general XII: science, research and development. Vol 1 (short version). Brussels: European Commission, 1996:16-7.
Of the 105 trials with interpretable results, 81 trials indicated positive results. Most studies showed results in favour of homeopathy even among those randomized controlled trials that received high- quality ratings for randomization, blinding, sample size, and other methodological criteria. They came to the following conclusion: "The amount of positive evidence even among the best studies came as a surprise to us. Based on this evidence we would readily accept that homeopathy can be efficacious, if only the mechanism of action were more plausible. The evidence presented in this review would probably be sufficient for establishing homeopathy as a regular treatment for certain indications". Kleijnen J, Knipschild P, Ter Riet G. Clinical trials of homoeopathy. British Medical Journal. 1991b;302:316-23.
A health technology assessment report on effectiveness, cost-effectiveness and appropriateness of homeopathy was compiled on behalf of the Swiss Federal Office for Public Health. Results showed a positive overall result in favour of homeopathy in 29 studies on upper respiratory tract infections and allergic reactions. Results also showed many high-quality investigations of pre-clinical basic research proved homeopathic high-potencies inducing regulative and specific changes in cells or living organisms. 20 of 22 systematic reviews detected at least a trend in favour of homeopathy. Boarnhoft G, Wolf U, Ammon K, Righetti M, Maxion-Bergemann S, Baumgartner S, Thurneysen AE, Matthiessen PF. Effectiveness, safety and cost-effectiveness of homeopathy in general practice – summarized health technology assessment. Forsch Komplementarmed. 2006; 13 Suppl 2: 19-29.
A meta-analysis of three trials on homeopathic immunotherapy. Result: significant effect in favour of homeopathic treatment. Reilly D, Taylor MA, Beattie NGM, Campbell JH, McSharry C, Aitchison TC, Carter R, Stevenson RD. Is evidence for homoeopathy reproducible? Lancet. 1994;344:1601-1606.
A review of placebo-controlled clinical trials using homeopathic medicines to treat people with AIDS or who are HIV-positive found 5 controlled clinical trials. Results showed statistically significant results in subjects with stage III AIDS, and specific physical, immunologic, neurologic, metabolic, and quality-of-life benefits, including improvements in lymphocyte counts and functions and reductions in HIV viral loads in patients receiving homeopathic treatment. Ullman D. Controlled Clinical Trials Evaluating the Homeopathic Treatment of People with Human Immunodeficiency Virus or Acquired Immune Deficiency Syndrome. The Journal of Alternative and Complementary Medicine. Volume 9, Number 1, 2003, pp. 133-141.
Meta-analysis of 105 articles on laboratory research. Result: positive effect 50% more frequently than negative effect among trials of highest methodological quality. (1994) Linde K. Jonas WB, Melchart D, Worku F, Wagner H, Eital F. Critical Review and Meta-Analysis of Serial Agitated Dilutions in Experimental Toxicology. Human and Experimental Toxicology. 1994;13:481-492
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