Smontato l'attacco di Lancet contro l'omeopatia  [05.11.2008]

 

Riportiamo nel link il comunicato stampa delle due associazioni professionali internazionali dei medici omeopati, l'ECH e la L.M.H.I., che riprendono e commentano i risultati di questi due nuovi studi.

Viene quindi pienamente dimostrata la posizione fin dall'inizio sostenuta anche dalla Società Italiana di Medicina Omeopatica [1]. Ecco quanto ha dichiarato a proporsiyo dello studio di Shang George Lewith, professore di Health Research alla università di Southampton: "Questo dimostra una insanabile debolezza nelle conclusioni (dello studio, ndt): NON sono affidabili"

Bibliografia

[1] Valeri A. La meta-analisi di Egger et al. sull’omeopatia permette di trarre conclusioni rilevanti per il sistema sanitario? Un’analisi metodologica critica.

Dr. Andrea Valeri, responsabile della ricerca scientifica, Società Italiana di Medicina Omeopatica.
Contatti: avaleri55@yahoo.it;
tel. +39 0535 26454;
mobile 349 888 04 63

 

Ecco il comunicato stampa in formato testo e più sotto gli abstracts dei due nuovi studi e dello studio originario di Lancet del 2005.

International Homeopathic Medical League LMHI, secretariat, Am Hofgarten 5, 53113 Bonn, Germany, tel.+49-228-2425330, email: generalsecretary@lmhint.net
European Committee for Homeopathy ECH, secretariat, Chaussée de Bruxelles 132, box 1, 1190 Brussels, Belgium, tel. +32-2-3453597, email: info@homeopathyeurope.org



Public release date: 3-Nov-2008, National Center for Homeopathy, 860-674-1500

New evidence for Homeopathy


Two new studies conclude that a review which claimed that homeopathy is just a placebo, published in The Lancet, was seriously flawed.

George Lewith, Professor of Health Research at Southampton University comments:‘The review gave no indication of which trials were analysed nor of the various vital assumptions made about the data. This is not usual scientific practice. If we presume that homeopathy works for some conditions but not others, or change the definition of a ‘larger trial’, the conclusions change. This indicates a fundamental weakness in the conclusions: they are NOT reliable.’

The background to the ongoing debate is as follows:

In August 2005, The Lancet published an editorial entitled ‘The End of Homeopathy’, prompted by a review comparing clinical trials of homeopathy with trials of conventional medicine. The claim that homeopathic medicines are just placebo was based on 6 clinical trials of conventional medicine and 8 studies of homeopathy but did not reveal the identity of these trials. The review was criticised for its opacity as it gave no indication of which trials were analysed and the various assumptions made about the data.

Sufficient detail to enable a reconstruction was eventually published and two recently published scientific papers based on such a reconstruction challenge the Lancet review, showing that:

    • Analysis of all high-quality trials of homeopathy yields a positive conclusion.
    • The 8 larger higher-quality trials of homeopathy were all for different conditions; if homeopathy works for some of these but not others the result changes, implying that it is not placebo.
    • The comparison with conventional medicine was meaningless.
    • Doubts remain about the opaque, unpublished criteria used in the review, including the definition of ‘higher quality’.

The Lancet review, led by Prof Matthias Egger of the Department of Social and Preventive Medicine at the University of Berne, started with 110 matched clinical trials of homeopathy and conventional medicine, reduced these to ‘higher-quality trials’ and then to 8 and 6 respectively ‘larger higher-quality trials’. Based on these 14 studies the review concluded that there is ‘weak evidence for a specific effect of homoeopathic remedies, but strong evidence for specific effects of conventional interventions’.

There are a limited number of homeopathic studies so it is quite possible to interpret these data selectively and unfavourably, which is what appears to have been done in the Lancet paper. If we assume that homeopathy does not work for just one condition (Arnica for post-exercise muscle stiffness), or alter the definition of ‘larger trial’, the
results are positive. The comparison with conventional medicine was meaningless: the original 110 trials were matched, but matching was lost after they were reduced to 8 and 6. But the quality of homeopathic trials was better than conventional trials.

This reconstruction casts serious doubts on the review, showing that it was based on a series of hidden judgments unfavourable to homeopathy. An open assessment of the current evidence suggests that homeopathy is probably effective for a number of conditions including allergies, upper respiratory tract infections and ‘flu, but more
research is desperately needed.

Prof Egger has declined to comment on these findings.


References
Lüdtke R, Rutten ALB. The conclusion on the effectiveness of homeopathy highly depend on the set of analysed trials. Journal of Clinical Epidemiology, 2008.
doi:10.1016/j.jclinepi.2008.06.015
Rutten ALB, Stolper CF. The 2005 meta-analysis of homeopathy: analysis of postpublication data. Homeopathy, 2008.
doi:10.1016/j.homp.2008.09.008.

For further information, please contact:
Prof George Lewith Tel: +44 7970 067884 email: gl3@soton.ac.uk
Rainer Lüdtke Tel: +49 201 5630516 email: r.luedtke@carstens-stiftung.de
Dr Lex Rutten Tel: +31 765 227340 email: lexrtn@concepts.nl

 

1) J Clin Epidemiol. 2008 Sep 30.

The conclusions on the effectiveness of homeopathy highly depend on the set ofanalyzed trials.
Lüdtke R, Rutten AL. Karl und Veronica Carstens-Stiftung, Essen, Germany.


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 (I(2)=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 successivel 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.



2) Homeopathy, Volume 97, Issue 4, , October 2008, Pages 169-177.

The 2005 meta-analysis of homeopathy: the importance of post-publication data

A.L.B. Rutten, C.F. Stolper


Background

There is a discrepancy between the outcome of a meta-analysis published in 1997 of 89 trials of homeopathy by Linde et al and an analysis of 110 trials by Shang et al published in 2005, these reached opposite conclusions. Important data were not mentioned in Shang et al's paper, but only provided subsequently.

Questions

What was the outcome of Shang et al's predefined hypotheses? Were the homeopathic and conventional trials comparable? Was subgroup selection justified? The possible role of ineffective treatments. Was the conclusion about effect justified? Were essential data missing in the original article?

Methods

Analysis of post-publication data. Re-extraction and analysis of 21 higher quality trials selected by Shang et al with sensitivity analysis for the influence of single indications. Analysis of comparability. Sensitivity analysis of influence of subjective choices, like quality of single indications and of cut-off values for ‘larger samples’.

Results

The quality of trials of homeopathy was better than of conventional trials. Regarding smaller trials, homeopathy accounted for 14 out of 83 and conventional medicine 2 out of 78 good quality trials with n < 100. There was selective inclusion of unpublished trials only for homeopathy. Quality was assessed differently from previous analyses. Selecting subgroups on sample size and quality caused incomplete matching of homeopathy and conventional trials. Cut-off values for larger trials differed between homeopathy and conventional medicine without plausible reason. Sensitivity analyses for the influence of heterogeneity and the cut-off value for ‘larger higher quality studies’ were missing. Homeopathy is not effective for muscle soreness after long distance running, OR = 1.30 (95% CI 0.96–1.76). The subset of homeopathy trials on which the conclusion was based was heterogeneous, comprising 8 trials on 8 different indications, and was not matched on indication with those of conventional medicine.
Essential data were missing in the original paper.

Conclusion

Re-analysis of Shang's post-publication data did not support the conclusion that homeopathy is a placebo effect. The conclusion that homeopathy is and that conventional is not a placebo effect was not based on comparative analysis and not justified because of heterogeneity and lack of sensitivity analysis.
If we confine ourselves to the predefined hypotheses and the part of the analysis that is indeed comparative, the conclusion should be that quality of homeopathic trials is better than of conventional trials, for all trials (p = 0.03) as well as for smaller trials (p = 0.003).

 

3) Lancet. 2005 Aug 27-Sep 2;366(9487):726-32.

Are the clinical effects of homoeopathy placebo effects? Comparative study of placebo-controlled trials of homoeopathy and allopathy.

Shang A, Huwiler-Müntener K, Nartey L, Jüni P, Dörig S, Sterne JA, Pewsner D,
Egger M. Department of Social and Preventive Medicine, University of Berne, Berne, Switzerland.

BACKGROUND: Homoeopathy is widely used, but specific effects of homoeopathic remedies seem implausible. Bias in the conduct and reporting of trials is a possible explanation for positive findings of trials of both homoeopathy and conventional medicine. We analysed trials of homoeopathy and conventional medicine and estimated treatment effects in trials least likely to be affected by bias.
METHODS: Placebo-controlled trials of homoeopathy were identified by 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 (issue 1, 2003).
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.
FINDINGS: 110 homoeopathy trials and 110 matched conventional-medicine trials were analysed. The median study size was 65 participants (range ten to 1573). 21 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 (95% CI 0.65-1.19) for homoeopathy (eight trials) and 0.58 (0.39-0.85) for conventional medicine (six
trials).
INTERPRETATION: 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.
This finding is compatible with the notion that the clinical effects of homoeopathy are placebo effects.

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