The practice of homeopathy is worldwide, but the medical and scientific communities are reluctant to give much credence to its two theoretical tenets: similars and dilutions.
Yet a systematic review in 1991 of 107 controlled, clinical trials of homeopathy by Kleijnen et al. showed a surprising number of positive results.2
Because many scientists view the principles of homeopathy as implausible, they have hypothesized that the positive results found in homeopathic trials are the result of the placebo effect. Now a recent paper published in The Lancet by Klaus et al.1 has conducted a meta-analysis of 89 trials to test that hypothesis.
The data collection for this effort was quite extensive:
| Selection data | Number |
| Controlled trials | 186 |
| Clinical trials | 171 |
| Placebo trials | 133 |
| Randomised and/or double-blind | 119 |
| Descriptive data | Number |
| Countries | 13 |
| Languages | 4 |
| Years | 1943-95 |
| Number of remedies | 50 |
| Patients |
| Total number | 10523 |
| Mean | 118 |
| Range | 5-1306 |
Klaus et al. sought studies in any language from "computerised bibliographies and contacts with researchers, institutions, manufacturers, individual collectors, homoeopathic conference proceedings, and books." Of the 186 trials, 119 met the inclusion criteria, and 89 had sufficient data for meta-analysis. This paper includes 145 references. Of the studies considered:
- 33 (37%) used "low" dilutions, 20 (22%) "medium" dilutions, and 31 (37%) "high" dilutions.
- 13 (15%) trials used the "classical" model of homoeopathy, 49 (55%) the "clinical" model, 20, (22%) the "complex" model, and seven (8%) used "isopathy."
The findings of the meta-analysis were that the positives results of homeopathic remedies were not just the result of a placebo effect:
"The combined odds ratio for the 89 studies entered into the main meta-analysis was 2.45 (95% Cl 2.05, 2.93) in favour of homoeopathy. The odds ratio for the 26 good-quality studies was 1.66 (1.33, 2.08), and that corrected for publication bias was 1.78 (1.03, 3.10). Four studies on the effects of a single remedy on seasonal allergies had a pooled odds ratio for ocular symptoms at 4 weeks of 2.03 (1.51, 2.74). Five studies on postoperative ileus had a pooled mean effect-size-difference of -0.22 standard deviations (95% Cl -0.36, -0.09) for flatus,and -0.18 SDs (-0.33, -0.03) for stool (both p<0.05). "The results of our meta-analysis are not compatible with the hypothesis that the clinical effects of homoeopathy are completely due to placebo. However, we found insufficient evidence from these studies that homoeopathy is clearly efficacious for any single clinical condition. Further research on homoeopathy is warranted provided it is rigorous and systematic."
As is the case with many forms of care, the lack of a significant number of high-quality studies prevented the investigators from concluding the effectiveness of homeopathy that many users would have liked. The researchers noted this problem and made particular efforts to provide suggestions for future research:
"Our impression from detailed examination of these trials, however, is that about two-thirds were methodologically poor, a third reasonable, and a tenth very good. Much of this research reflects the lack of infrastructure needed to conduct good studies and develop appropriate research strategies in this area. "Our study does, however, have major implications for future research on homoeopathy. We believe that a serious effort to research homoeopathy is clearly warranted despite its implausibility. Deciding to conduct research on homoeopathy recognises that this approach is a relevant social and medical phenomenon.
"What then is a reasonable strategy for approaching this are? "One approach is to develop laboratory models that explore possible mechanisms3,4 or attempt independent replication of the simpler clinical models that already exist, such as the studies by Reilly et al.5 or Wiesenauer et al.6,7,8,9 on seasonal allergies.
"Another approach would be to separate research addressing whether homoeopathy is placebo (the academic question currently dominating the debate) more clearly from research exploring whether or not it provides a useful tool in health care (the question of more relevance to patients and health-care providers). To do this, much more detailed information is needed on who is treated with homoeopathy (population characteristics), the reliability of homoeopathic classifications (clinical accuracy), how homoeopathy is applied (standards and decision models and practice), and response rates (effect sizes) of these approaches on specific conditions. This type of detailed clinical information is obtainable from prospective observational studies and would allow for rational planning of randomised trials that truly reflect homoeopathic practice and have clinical and scientific implications."
References - Linde K, Calusius N, Ramirez G, Melchart D, Eitel F, Hedges LV, Jonas WB. Are the clinical effects of homoeopathy placebo effects? A meta-analysis of placebo-controlled trials. Lancet 1997;350:834-43.
- Kleijnen J, Knipschild P, ter Riet G. Clinical trials of homoeopath. BMJ 1991;302:316-23.
- Sainte-Laudy J, Belon P. Application of flow cytometry to the analysis of the immunosuppressive effect of histamine dilutions on human basophil activation: Effect of cimetidine. Inflamm Res 1997; 46: S27-28.
- Endler PC, Pongratz W, Kastberger G. Wiegant FAC, Schulte J. The effect of highly diluted thyroxine on the climbing activity of frogs. Vet Hum Toxicol 1994; 36: 56-59.
- Zell J, Connert WD, Mau J, Feuerstake G. Behandlung von akuten Sprunggelenksdistorsionen. Fortschr med 1988; 106: 96-100.
- Wiesenauer M, Gaus W. Double-blind trial comparing the effectiveness of the homoeopathic preparation Galphimia potentisation D6, galphimia dilution 10 and placebo on pollinosis. Arzneimittelforschung 1985; 35: 1745-47.
- Wiesenauer M, Gaus W. Haussler S. Behandlung der Pollinosis mit Galphimia glauca, Eine Doppelblindstudie unter Praxisbendingungen. Allergologie 1990; 13: 359-63.
- Wiesenauer M, Haussler S, Gaus W, Pollinosis-Therapie mit Galphimia glauca. Fortschr Med 1983; 101: 811-14.
- Wiesenauer M, Ludtke R. The treatment of pollinosis with Galphimia glauca D4 -- a randomized placebo-controlled double-blind clinical trial. Phytomedicine 1995; 2: 3-6.
