]Overview
Figure 3 compares the underlying patterns from the four trials based on daily visual analogue scale data from all 253 randomised patients and the main objective measures. The subjective changes measured by the visual analogue scale show a therapeutic response from homoeopathy across the four trials. There was a lesser and more variable response in the placebo groups, which probably accounts for the evidence of some statistical heterogeneity (χ2=9.04, df=3, P=0.03). The pooled estimate of the treatment effect (middle column, fig 3) showed an average improvement in visual analogue scores in the homoeopathy group compared with the placebo group (improvement 11.1 mm, 95% confidence interval 3.3 to 18.8; P<0.01). Thus, overall, the trend of the individual trial results and pooled data point towards homoeopathy differing from placebo. The trends in the objective measures all follow the same direction as the subjective measures (fig 3), again indicating a difference between a homoeopathic dilution and placebo.
Figure 4 shows the average response to homoeopathic immunotherapy over time in the four trials. A distinct separation emerges between the action of homoeopathy and placebo. On average, over the last two weeks after randomisation, patients who received homoeopathy had a 28% improvement compared with 3% among those in the placebo group. There was a mean reduction of the visual analogue scale score of 10.9 mm in the homoeopathy group compared with 1.1 mm in the placebo group (95% confidence interval for difference 4.2 to 15.4, P=0.0007; two sided, two sample t test).
We found that homoeopathy and placebo had different effects. Compared with placebo, homoeopathy provoked a clear, significant, and clinically relevant improvement in nasal inspiratory peak flow, similar to that found with topical steroids.15 However, the subjective improvement was less clear. Although the objective measure consistently improved in all five centres, the subjective results were better than placebo in only four of the five centres and overall there was no difference between the groups. If the objective results are valid the discrepancy in the subjective measurements may be partly due to under recruitment compounded by aggravations and possible initial placebo responses during the run-in period in both groups, perhaps reflecting the positive expectations of the participants.23 Patients with rhinitis are keen to enter studies in their quest for better symptom control.24 Subjective improvement began before the end of the placebo run-in phase in both groups, and this lessened the chance of distinguishing between the groups.25 26 A larger sample size may have shown a subjective difference between the groups.
More initial aggravations occurred in patients who received homoeopathy, and this may have further complicated the subjective results. The pattern of temporary worsening followed by improvement, seen in this trial and observed in clinical homoeopathy for over 200 years,27 28 is not typical of placebo.
Validity of results
Like any other therapy, homoeopathy requires rigorous scientific testing, and one study is insufficient evidence. Some perspective may be gleaned by viewing the results of this trial in the context of the series of which it is part. Except for the subjective measure in this fourth trial, the subjective and objective results show a trend across these four trials clearly pointing to homoeopathy being different from placebo. If the results were due to chance then some trends in favour of placebo would be expected. So does homoeopathy work or are our results due to some other factor?
Recent attempts to resolve the controversy surrounding homoeopathy have centred on the 180 or so controlled trials to date. A criteria based review in 1991 found that the evidence was positive but not conclusive.29 In a 1997 update, other workers concluded that 73% of the existing trial data supported homoeopathy being more effective than placebo, with the pooled odds ratio from a criteria based meta-analysis of 89 trials suggesting homoeopathy showed around twice the overall mean effect of placebo. The difference was significant and proved robust in sensitivity analyses that included correction for publication bias.30 A third working group, independently set up by the European Commission, selected 17 comparisons in 2001 patients for a meta-analysis. The pooled P value was highly significant, and the group commented that “it is likely that among the tested homeopathic approaches some had an added effect over nothing or placebo.â€31 Are these findings “meta-errors†or, however implausible, does something tangible lie at the core of homoeopathy?
To interpret these findings as arguing for homoeopathy having an effect may now be more plausible than our previous hypothesis of serial false positive results.3 32 For now, we conclude that this study has failed to confirm our original hypothesis that homoeopathy is a placebo.http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pubmed&pubmedid=10948025