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Natalie Lane is production editor for
journals at the Pharmaceutical Press, London
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A focus article by Alyson Huntley in the March issue of Focus on
Alternative and Complementary Therapies searches for randomised controlled trials
(RCTs) of therapies for diabetic neuropathy with clinical outcomes. Databases
such as Medline and the Cochrane Library were searched and, from the
studies found, bibliographies were also scanned for further trials. As
a result, 23 RCTs covering diabetic neuropathy and complementary and
alternative medicine were found and the article discusses the range of
CAM approaches used.
The results detail the following CAM approaches: alpha lipoic acid (ALA),
vitamins, gamma linoleic acid (GLA), capsaicin, acetyl L-carnitine (ALC),
traditional Chinese medicine, zinc and magnetised insoles.
The results included seven RCTs using the antioxidant ALA with daily
doses of 100–1,200mg and the trials suggested that ALA was of benefit
in symptomatic diabetic polyneuropathy. The author also details a recent
meta-analysis to determine efficacy and safety of 600mg of ALA given
intravenously during three weeks. The analysis compared the differences
in total symptom score (TSS) and, after three weeks, the relative difference
in favour of ALA versus placebo was 24.1 per cent.
Four RCTs were found that concerned vitamin supplementation, with the
trials investigating vitamin B6, B12 and a vitamin B complex. The results
suggest “some effect on neuropathic symptoms” but, overall,
it was difficult to draw “meaningful conclusions”.
From three RCTs using GLA, only one complete paper could be viewed and
this reported patients taking 480mg of GLA daily and resulted in 13 of
16 parameters being “statistically significantly improved” compared
with placebo. However, a recent study, only available as an abstract,
saw no effect on automatic functioning in diabetic patients after 12
months of a GLA dose at the same amount. The author notes that the two
trials are different in their profile of outcome
measures.
The author says there is a range of beneficial CAM approaches to diabetic
neuropathy available, with evidence of ALA and capsaicin being of benefit
to the condition and B vitamins and GLA of possible benefit. She concludes
by emphasising the importance of the fact that the RCT data did not reveal
any apparent safety issues.
Ginseng and colds prevention
FACT highlights, in the summaries and commentaries section, a clinical
trial of Panax quinquefolium (North American ginseng) root for the prevention
of colds. A double-blind, placebo-controlled RCT had 279 subjects take
400mg of a freeze-dried derivative of a North American ginseng extract
or placebo for four months. The results saw fewer people with two or
more colds, and total symptom scores and days of illness were reduced
in the ginseng group. The authors concluded that the ginseng formulation
used appears to be an attractive natural prophylactic treatment for upper
respiratory tract infections.
The commentator’s initial scepticism of the article was dissipated
by the authors’ attention to the study methodology and proper reporting
of the clinical trial, including a summary of the description of the
drop-outs and method of randomisation being well defined. There is discussion
about the difficulty of hypothesising a mechanism of action for the immunomodulatory
effects of ginseng and that there are “few in vivo analyses of
relevant immunological parameters”. It is thought that this study
reflected such confusion and that the outcomes of cold symptoms are non-specific.
However, the commentator reflects that the article provides useful information
for a growing body of literature about the clinical effect of Panax spp
but is mindful that there is a need for mechanistic studies.
In response, the article’s corresponding author clarifies that
the study product was not ginseng but COLD-fx, a patented derivative
obtained from North American ginseng. Information about COLD-fx had been
removed from the published article despite the authors’ view that
it was critical in supporting the study’s scientific integrity.
The authors agree about the difficulty of hypothesising a mechanism of
action for ginseng’s immunomodulatory effects, as raised by the
commentator. However, they note that the study concerned only an extract
of ginseng. The authors also note that studies show this product as having “the
potential to enhance immune systems” and such findings are important
to the study being reviewed.
Homoeopathy and allopathic medicine
Another summary and commentary examined the clinical effects of homoeopathy
in placebo-controlled trials and whether they are explained by methodological
deficiencies and biased reporting. The authors identified placebo-controlled
trials of homoeopathy and then identified an equal number of conventional
medicine trials matched for similar disorders and similar outcomes.
They matched 105 publications of 110 trials with 110 conventional trials.
Then they used a protocol to decide the main outcome of the study and,
without knowledge of the results, outcomes were selected and trials
matched. The quality of trials was assessed using three aspects of
internal validity: randomisation, masking and analysis. The authors
concluded that biases were present in both sets of trials and, taking
this factor into account, showed “weak evidence for a specific
effect of homoeopathy, but strong evidence for a specific effect of
conventional medicine”. Even with meta-analysis of homoeopathy
trials in a specific clinical area showing significant effect, the
authors state that “the results cannot be trusted” and
that there “is little value in pursuing further trials in homoeopathy”.
The commentator is sceptical about the validity of “pooling results
from across a whole area of CAM”. It is thought that it is not
clear what “similar disorders” or “similar outcomes” are,
with no justification presented by the authors regarding the criteria
for matching data and subsequently no information presented about the
differences within the pairs. Indeed, the commentator says that, despite
selecting the two sets of trials, the matched data are subsequently ignored
and results about “relative treatment effectiveness” within
the pairs of trials could have been discussed. The commentator further
discusses the analyses done and the selection of “larger trials
of higher quality”.
The commentator states this to be a controversial paper. The authors’ stated
prior belief that “effects … could be explained by a combination
of methodological deficiencies and biased reporting” is proved
consistent with the paper’s results but the commentator wonders
if there are other explanations for the results and argues that these
results are based on methods that may not be entirely valid, therefore
seem to be over-stated, and the conclusions difficult to believe. |
The
Pharmaceutical Journal