Homeopathic remedies create doubts

Homoeopathy is a widely used alternative system of medicine, but the benefits of homoeopathic remedies seem doubtful. Bias in the conduct and reporting of trials is a possible explanation for positive findings of trials of both homoeopathy and conventional medicine. Researchers from the United Kingdom analysed trials of homoeopathy and conventional medicine and estimated treatment effects in trials least likely to be affected by bias. The researchers did a comprehensive literature search, which covered 19 electronic databases, reference lists of relevant papers, and contacts with experts. Trials in conventional medicine matched to homoeopathy trials for disorder and type of outcome were randomly selected from the Cochrane Controlled Trials Register. Data were extracted in duplicate and outcomes coded so that odds ratios below 1 indicated benefit. Trials described as double-blind, with adequate randomisation, were assumed to be of higher methodological quality. Bias effects were examined in funnel plots and meta-regression models. Investigators analysed 110 homoeopathy trials and a similar number of matched conventional-medicine (allopathy) trials. Twenty-one homoeopathy trials (19%) and nine (8%) conventional-medicine trials were of higher quality. In both groups, smaller trials and those of lower quality showed more beneficial treatment effects than larger and higher-quality trials. When the analysis was restricted to large trials of higher quality, the odds ratio was 0·88 for homoeopathy (eight trials) and 0·58 for conventional-medicine (six trials). It was concluded that biases are present in placebo-controlled trials of both homoeopathy and conventional medicine. When account was taken for these biases in the analysis, there was weak evidence for a specific effect of homoeopathic remedies, but strong evidence for specific effects of conventional interventions. Hence, this finding indicates that the clinical effects of homoeopathy are placebo effects. In a similar vein, the Swiss Government, after a five year trial, has now withdrawn insurance coverage for homeopathy and four other complementary treatments because they did not meet efficacy and cost-effectiveness criteria.