Are the Effects of Homeopathy Attributable to a Statistical Artefact? A Reanalysis of an Observational Study

Background. Cohort studies have reported that patients improve considerably after individualised homeopathic treatment. However, these results may be biased by regression to the mean (RTM).Objective. To evaluate whether the observed changes in previous cohort studies are due to RTM and to estimate RTM adjusted effects.Methods. SF-36 quality-of-life (QoL) data from a German cohort of 2827 chronically diseased adults treated by a homeopath were reanalysed by Mee and Chua’s modifiedt-test.Results. RTM adjusted effects, standardized by the respective standard deviation at baseline, were 0.12 (95% CI: 0.06–0.19,P<0.001) in the mental and 0.25 (0.22–0.28,P<0.001) in the physical summary score. Small-to-moderate effects were confirmed for the most individual diagnoses in physical, but not in mental component scores. Under the assumption that the true population mean equals the mean of all actually diseased patients, RTM adjusted effects were confirmed for both scores in most diagnoses.Conclusions. Changes in QoL after treatment by a homeopath are small but cannot be explained by RTM alone. As all analyses made conservative assumptions, true RTM adjusted effects are probably larger than presented.

Histamine iontophoresis on the viability of random skin flap in rats

PURPOSE: To evaluate the effects of the histamine iontophoresis on the random skin flap viability in rats. METHODS: Sixty adult male Wistar rats were used. A cranially-based dorsal skin flap measuring 10 x 4 cm was raised and a plastic barrier was placed between the flap and its bed. After the surgical procedure, the animals were randomized into four groups (G1-G4) (n=15 each group) as follows: G1 (control) - sham electrical stimulation, G2 (electrical stimulation) - direct current electrical stimulation, G3 (histamine) - histamine and sham electrical stimulation and G4 (histamine iontophoresis) - transdermal iontophoresis of histamine. In all groups the procedures were performed immediately after the surgery and on the two subsequent days. The percentage of flap necrosis was measured on the seventh postoperative day. RESULTS: The mean and the respective standard deviation of the percentage of flap necrosis areas were as follows: G1 (control) - 47.87 ± 9.13%, G2 - 51.49 ± 8.19%, G3 - 46.33 ± 8.32% and G4 - 30.82 ± 11.25%. The G4 group presented a significantly smaller amount of flap necrosis when compared to the other groups (p<0.001). CONCLUSION: The topical administration of the histamine by iontophoresis was effective to increase the viability of the random skin flaps in rats.

Reply by Dr. Rosenbach

The errors involved in the second derivative coefficient sets of Elkins and myself are not as divergent as one would expect from the respective standard deviation figures, [Formula: see text] and [Formula: see text], given by the authors of the discussion.