Randomized controlled trials of individualized homeopathy: A state-of-the-art review

Background and objective: Individualized homeopathy is the most controversial form of this therapy. This review aims to summarize the actual state of clinical efficacy research on individualized homeopathy. Methods: Electronic databases as well as other sources were searched for possibly relevant studies. Randomized or quasirandomized controlled clinical trials comparing an individualized homeopathic treatment strategy with placebo, no treatment, or another treatment were eligible. Information on patients, methods, interventions, outcomes, and results was extracted in a standardized manner and quality was assessed using a checklist and two scoring systems. Trials providing sufficient data were pooled in a quantitative meta-analysis. Results: A total of 32 trials (28 placebo-controlled, 2 comparing homeopathy and another treatment, 2 comparing both) involving a total of 1778 patients met the inclusion criteria. The methodological quality of the trials was highly variable. In the 19 placebo-controlled trials providing sufficient data for meta-analysis, individualized homeopathy was significantly more effective than placebo (pooled rate ratio 1.62, 95% confidence interval 1.17 to 2.23), but when the analysis was restricted to the methodologically best trials no significant effect was seen. Conclusion: The results of the available randomized trials suggest that individualized homeopathy has an effect over placebo. The evidence, however, is not convincing because of methodological shortcomings and inconsistencies. Future research should focus on replication of existing promising studies. New randomized studies should be preceded by pilot studies.