Ein Herr Aust und der Prof. Edzard Ernst sagen diese Woche, daß der Frass aufmüpfig ist:
[*quote*]
Prof Frass’ criticism of the Lancet meta-analysis of homeopathy: a rebuttal of a rebuttalPublished Wednesday 21 March 2018
by Norbert Aust as ‘guest blogger’ and Edzard Ernst
Professor Frass has repeatedly stated that his published criticism of the Lancet meta-analysis has never been refuted, and therefore homeopathy is a valid therapy. The last time we heard him say this was during a TV discussion (March 2018) where he said that, if one succeeded in scientifically refuting the arguments set out in his paper, one would show the ineffectiveness of homeopathy.
[und so weiter und so weiter...]
[*/quote*]
Möhrchen:
http://edzardernst.com/2018/03/prof-frass-criticism-of-the-lancet-meta-analysis-of-homeopathy-a-rebuttal-of-a-rebuttal/Der Leserbrief von Frass und Co. ist eine uralte Kamelle von 2006:
https://www.sciencedirect.com/science/article/pii/S147549160500158X?via%3Dihub[*quote*]
Homeopathy
Volume 95, Issue 1, January 2006, Pages 52-53
Homeopathy
LETTER TO THE EDITOR
Asymmetry in The Lancet meta-analysis
Author links open overlay panel
Michael Frass a, E Schuster b, Ilse Muchitsch c, Jeff Duncan d, Walter Geir d, Gloria Kozel e, Christa Kastinger-Mayr e, Anton E. Felleitner e, Christian Reiter f,
Christian Endler g, Menachem Oberbaum h
a Department of Internal Medicine I Medical University Vienna and Ludwig Boltzmann Institute for Homoeopathy, Vienna, Austria
b Core Unit of Medical Statistics and Informatics, Medical University Vienna, Vienna, Austria
c Interdisciplinary Homoeopathic Research Group, Austrian Pharmacists Association, Austria
d Doctors Association for Classical Homoeopathy
e Austrian Society for Homoeopathic Medicine, Austria
f Umbrella Organisation of Austrian Doctors for Holistic Medicine, Austria
g Interuniversity College for Health and Development, Graz, Austria
h The Center for Integrated Complementary Medicine Shaare Zedek Medical Center, Jerusalem
Available online 5 January 2006.https://doi.org/10.1016/j.homp.2005.11.009[*/quote*]
Über
"Michael Frass" und
"Christian Endler" haben wir schon Material, das sich sehen läßt. OH JE! Für Humor ist reichlich gesorgt.
11 Jahre hat sich niemand um den Quatsch gekümmert. Das muß Frass und Co. sehr betroffen gemacht haben.
Es darf gelacht werden:
http://www.ganzheitsmed.at/index.Dateien/2017_Homeopathy-Letter-2006.95.52.53.pdf[*quote*]
ARTICLE IN PRESS
Letters to the editor
[PAGE] 52
Asymmetry in The Lancet meta-analysisWe have read with interest the paper by Shang
et al. 1 We appreciate the efforts to undertake such
an enormous work. In the following we want to
express some comments from a scientific point of
view.
The exciting message is that homeopathy works, as
described in the Results section: in both groups a
beneficial effect was shown when all 110 studies were
taken into account (Figure 2). The authors also
acknowledge less pronounced heterogeneity for ho-
meopathy trials. In addition, a higher quality of
included studies was found in the homeopathy group
(19 vs 8%, Table 2).
While agreeing with the authors with respect to these
sensational results, we have major concerns about their
conclusions.
Firstly, even with careful selection, it remains
problematic to compare studies of a pool of 165 for
homeopathy vs 4200,000 for conventional medicine.
This factor of 41000 already contains asymmetry.
Furthermore, it appears that there is discrimina-
tion when publications in English (94/110, 85% in
the conventional medicine group vs 58/110, 53% in
the homeopathy group) are rated higher quality
(Table 2).
Neither the Summary nor the Introduction clearly
specify the aim of the study. Furthermore, the design
of the study differs substantially from the final analysis
and therefore the prolonged description of how the
papers and databases were selected is misleading:
instead of analysing all 110 studies retrieved by their
defined inclusion and exclusion criteria, the authors
reduce the number of investigated studies to ‘larger
trials of higher quality’. By using these sub-samples,
the results seem to differ between conventional
medicine and homeopathy.
The meta-analysis does not compare studies of
homeopathy vs studies of conventional medicine, but
specific effects of these two methods in separate
analyses. Therefore, a direct comparison must not be
made from this study.
However, there remains great uncertainty about the
selection of the eight homeopathy and the six conven-
tional medicine studies: the cut-off point seems to be
arbitrarily chosen: if one looks at Figure 2, the data
look very much the same for both groups. This holds
true even if various levels of SE are considered.
Therefore, the selection of larger trials of higher
quality is a post-festum hypothesis but not a pre-set
criterion. The question remains: was the restriction to
larger trials of higher quality part of the original
protocol or was this a data-driven decision? Since we
cannot find this proposed reduction in the abstract, we
doubt that it was included a priori.
However, even if one assumes that this was a pre-
defined selection, there are still some problems with the
authors’ interpretation: for larger trials of higher
reported methodological quality, the odds ratio was
0.88 (CI 95%: 0.65–1.19) based on eight trials of
homeopathy: although this finding does not prove an
effect of the study design on the 5% level, neither does
it disprove the hypothesis that the results might have
been achieved by homeopathy. For conventional
medicine, the odds ratio was 0.58 (CI 95%
0.39–0.85), which indicates that the results may not
be explained by mere chance with a 5% uncertainty.
There may be ‘evidence’ or ‘no evidence’ but not ‘weak
or strong evidence’.
Although the authors acknowledge that ‘to prove a
negative is impossible’ the authors clearly favour the
view that there is evidence that homoeopathy exhibits
no effect beyond the placebo-effect. However, this
conclusion was drawn after a substantial modification
of the original protocol which considerably weakens its
validity from the methodological point of view. After
acquiring the trials by their original inclusion- and
exclusion criteria they introduced a further criterion,
‘larger trials of higher reported methodological qual-
ity’. Thus, eight trials (1⁄4 46% of the larger trials) in the
homoeopathy group were left and only six (32%) in
conventional medicine group (an odds ratio of 0.75 in
favour of homoeopathy).
But the decisive point is that it is unlikely that these
six trials are still matched to the eight samples
of homoeopathy (although each of the 110 in the
original was matched). Consequently, one cannot
conclude that these trials are still comparable. Thus,
any comparisons of results between them are unjusti-
fied.
The rationale for this major alteration of the study
protocol was the assumption, that these larger, higher
quality trials are not biased, but no evidence or data-
based justification is given. Neither the actual data
(odds ratio, matching parameters...) nor a funnel plot
(to indicate that there is no bias) of the final 14 trials
are supplied although these parameters constitute the
ground of their conclusion.
The other 206 trials (94% of the originally selected
according to the protocol) were discarded because
of possible publication biases as visualized by the
funnel plots. However, the use of funnel plots is
also questionable. Funnel plots are thought to
detect publication bias, and heterogeneity to detect
fundamental differences between studies. New evi-
dence suggests that both of these common beliefs are
badly flawed.
Using 198 published meta-analyses, Tang and
Liu demonstrate that the shape of a funnel plot is
[PAGE] 53
largely determined by the arbitrary choice of the
method to construct the plot. 2 When a different
definition of precision and/or effect measure was
used, the conclusion about the shape of the plot was
altered in 37 (86%) of the 43 meta-analyses with
an asymmetrical plot suggesting selection bias. In
the absence of a consensus on how the plot should
be constructed, asymmetrical funnel plots should be
interpreted cautiously. These findings also suggest
that the discrepancies between large trials and corre-
sponding meta-analyses and heterogeneity in meta-
analyses may also be determined by how they are
evaluated.
Researchers tend to read asymmetric funnel plots as
evidence of publication bias, even though meta-
analyses without publication bias frequently have
asymmetric plots and meta-analysis with publication
bias frequently have symmetric plots, simply due to
chance. Use of funnel plots is even more unreliable
when there is heterogeneity. 3
Apart from the questionable selection of the samples
there is a further aspect of randomness which further
weakens their conclusion: the odds ratio of the eight
trials of homoeopathy was 0.88 (CI 0.65–1.19), which
might be significant around the 7–8% level. Actually,
the reader might be interested to know at which exact
level homeopathy would have become significant.
Thus, there is no support of their conclusion any
more when you shift the level of significance by mere,
say 2–3%. In addition, with such controversial
hypotheses the scientific community would tend to
use a level of significance of 1% in which case the odds
ratio of the conventional studies would not be
significant either.
From a statistical point of view, the power of
the test, considering the small sample sizes, should
have been stated, especially in the case of a non-
significant result. Above all, the choice of which
trials are to be evaluated is crucial. By choosing a
different sample of eight trials (eg the eight trials
in ‘acute infections of the upper respiratory tract’,
as mentioned in the Discussion section) a radi-
cally different conclusion would have had to be
drawn (namely a substantial beneficial effect of
homeopathy—as the authors state). The authors
may not be aware that larger trials are usually not
‘classical’ homeopathic interventions, because the
main principle of homeopathy, individualization are
difficult to apply in large trials. In this respect, the
whole study lacks sound understanding of what
homeopathy really is.
At the Medical University of Vienna, we tend to
investigate controversial issues on an academic basis.
We support the dialogue between conventional med-
icine and homeopathy. We hope that Lancet will be
open-minded for non-conventional medicine in the
future as it was in 1994 and 1997. 4,5
References
1 Shang A, Huwiler-Muntener K, Nartey L, et al. Are the clinical
effects of homoeopathy placebo effects? Comparative study of
placebo-controlled trials of homoeopathy and allopathy. Lancet
2005; 366: 726–732.
2 Tang J, Liu JL. Misleading funnel plot for detection of bias in
meta-analysis. J Clin Epidemiol 2000; 53: 477–484.
3 Terrin NC, Schmid CH, Lau J. Publication bias, chance, and
heterogeneity: how researchers interpret the funnel plot. Ninth
International Cochrane Colloquium, Lyon, France, 9–13 October
2001. Cochrane 2001; 1: op006.
4 Reilly DT, Taylor MA, Beattie NGM, et al. Is evidence for
homoeopathy reproducible? Lancet 1994; 344: 1601–1606.
5 Linde K, Clausius N, Ramirez G, et al. Are the clinical effects of
homoeopathy placebo effects? A meta-analysis of placebo-
controlled trials. Lancet 1997; 350: 834–843.
Michael Frass
Department of Internal Medicine I Medical University
Vienna and Ludwig Boltzmann Institute for
Homoeopathy, Vienna, Austria
E-mail: michael.frass@meduniwien.ac.at
E Schuster
Core Unit of Medical Statistics and Informatics, Medical
University Vienna, Vienna, Austria
Ilse Muchitsch
Interdisciplinary Homoeopathic Research Group,
Austrian Pharmacists Association, Austria
Jeff Duncan and Walter Geir
Doctors Association for Classical Homoeopathy
Gloria Kozel, Christa Kastinger-Mayr and Anton
E Felleitner
Austrian Society for Homoeopathic Medicine, Austria
Christian Reiter
Umbrella Organisation of Austrian Doctors for Holistic
Medicine, Austria
Christian Endler
Interuniversity College for Health and Development,
Graz, Austria
Menachem Oberbaum
The Center for Integrated Complementary Medicine
Shaare Zedek Medical Center, Jerusalem
[*/quote*]
Oh, Entschuldigung, hätte ich eine Cola-Warnung geben sollen? Man gönnt sich doch sonst nichts.
For the usual suspects.
