[Omeo33] Art 0896 - J Clin Epidemiol, 2008, doi:10.1016/j.jclinepi.2008.06.015

[Gino Santini]

The conclusions on the effectiveness of 
homeopathy highly depend on the set of analyzed 
trials
R. Lüdtke and A.L.B. Rutten

Objective - Shang's recently published 
meta-analysis on homeopathic remedies (Lancet) 
based its main conclusion on a subset of eight 
larger trials out of 21 high quality trials out 
of 110 included trials. We performed a 
sensitivity analysis on various other meaningful 
trial subsets of all high quality trials.
Study Design - Subsets were defined according to 
sample size, type of homeopathy, type of 
publication, and treated disease/condition. For 
each subset, we estimated the overall odds ratios 
(ORs) from random effect meta-analyses.
Results - All trials were highly heterogeneous 
(I2 = 62.2%). Homeopathy had a significant effect 
beyond placebo (OR = 0.76; 95% CI: 0.59-0.99; p = 
0.039). When the set of analyzed trials was 
successively restricted to larger patient 
numbers, the ORs vary moderately (median: 0.82, 
range: 0.71-1.02) and the P-values increased 
steadily (median: 0.16, range: 0.03-0.93), 
including Shang's results for the eight largest 
trials (OR = 0.88, CI: 0.66-1.18; P = 
0.41).Shang's negative results were mainly 
influenced by one single trial on preventing 
muscle soreness in N = 400 long-distance runners.
Conclusions - The meta-analysis results change 
sensitively to the chosen threshold defining 
large sample sizes. Because of the high 
heterogeneity between the trials, Shang's results 
and conclusions are less definite as they had 
been presented.

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