主题：贴，贴， -- 虽远必诛
5. Duration of fever
Five trials reported no difference in the duration of fever between
the intervention and control groups. Two of these trials reported
no difference in the number of participants whose temperatures
were normalised within 24 hours (Chang 2002), 48 hours and 72
hours (Yu 1997): Sanhan Jiere Koufuye versus (Fenghan) Biaoshi
Ganmao Chongji (RR 1.02 95% CI 0.85 to 1.22) (Chang 2002);
and Caichen Qinre Weixin Guanchangji versus virazole and acetaminophen
(RR 1.46, 95% CI 0.89 to 2.40, and RR 0.33, 95%
CI 0.11 to 0.99, respectively) (Yu 1997).
Likewise, another three trials (Chang 2002; Chang 2005; Wang
2008a) showed no difference in duration of fever between the two
groups (WMD -0.29 hours, 95% CI -2.26 to 1.68, WMD -3.91
hours, 95%CI -8.24 to 0.42,WMD 4.20 hours, 95%CI -1.41 to
9.81 and WMD 3.62 hours, 95% CI -2.74 to 9.98, respectively).
Three trials (Chang 2005; Li 1998; Wang 1998) reported a statistically
significantly shorter duration of fever in the treatment
group compared to the control group 2.02, 6.90 and 5.70 hours,
respectively (WMD -2.02, 95% CI -3.86 to -0.18; WMD -6.90,
95% CI -9.94 to -3.86, and WMD -5.70, 95% CI -10.09 to -
1.31, respectively). One study (Li 1998) showed that in the treatment
group the average duration of fever was longer than control
group by 11.60 hours (WMD -11.60, 95% CI -15.65 to -7.55).
Another trial (Wang 2008a) showed no statistically significant differences
in the time to resolution of fever in the treatment group
A and B as compared to the control group (WMD -2.06 hours,
95% CI -5.02 to 0.90, and WMD -1.44 hours, 95% CI -4.70 to
1.82).
6. Adverse events
None of the trials reported any adverse events, according to our
definitions.
7. Additional outcomes
Seven trials (Chang 2002; Chang 2005; Chang 2007; Chen 2004;
Wang 2004; Wang 2008a; Yu 2005) reported effects on TCM
signs. We only analysed data in two studies (Chang 2005; Chen
2004). There were no statistically significant differences between
the two groups in these trials.
D I S C U S S I O N
Summary of main results
Studies of Chinese herbal medicines for the common cold lack
sufficient power to provide reliable estimates of their efficacy, due
to poor study design and methodological quality.
Although Chinese herbal medicines as a treatment for the common
cold and the methods of manufacturing these medicines are
widely accepted in China, most of the constituents of the pharmacologically
prepared drugs used in trials cannot be specified.
This is in marked contrast to the pharmacological agents used
in Western medicine, for which the chemical constituents, their
quantities and the percentage of any impurities or contaminants
are precisely known. In addition, the variation between different
production batches of Western medicines is kept within specified
limits. In contrast, variation between formulations and batches
of pharmacological agents are inevitable in traditional Chinese
medicine (TCM), although the Chinese Government specifies the
acceptable limits of variation. This variation is a factor that may
contribute to any heterogeneity between different study results.
A large number of the trials initially identified claimed to be randomised
controlled trials (RCTs). However, after contacting the
trial authors to request information regarding the method of randomisation
used, we found that more than 95% of the authors
misunderstood the concept of randomisation. In addition to this,
some of the studies were conducted several years ago, and the trial
authors may have forgotten the details of the methodology they
employed. This could lead to a memory bias and undermine the
veracity of information.
Some studies (Chang 2002; Li 1998; Li 1999a; Ma 2000; Wang
2004; Yang 2000; Yu 1997) used unequal arms in their design.
Of these studies, Yu 1997 used a proportion of 3:1, and only 15
patients were included in the control group (43:15). However,
consideration of the sample sizes was not reported in these trials,
which makes it difficult to detect the differences between the two
groups accurately. This may lead to a low test power.
Finally, we considered it pertinent to attempt to compare selected
TCMsigns in different groups of participants. TCMsigns are difficult
to quantify because they use subjective outcomes. For example,
’wu han’ means that the participant feels cold whilst also
having a fever, and this can be divided into low, medium and high
categories, depending on the participants’ subjective view. ’Mai xiang’measures
the pulse; in TCMit is a complex and difficult technique
to judge this accurately and often dependent upon on the
physician’s experience.TCMresearchers and physicians should decide
upon an accurate and consistent method of measuring TCM
signs.
Quality of the evidence
None of the trials included in this review used a placebo as a control:
instead “positive effect drugs” were selected. Two studies (
Chang 2005; Chang 2007) mentioned that the rule of selecting
the control drug was that “the effect was generally acknowledged”.
This may result in false positive findings, as a number of interventions
are considered effective for the common cold, particularly if
trial conductors know that a “positive” drug was used in the trial
and the purpose of the study was to demonstrate the same effect
as the control (so called “equal effect test”). For example, Chang
2005 compared two different forms of the same ingredient. In this
Chinese medicinal herbs for the common cold (Review) 13
Copyright 2009 The Cochrane Collaboration. Published by JohnWiley & Sons, Ltd.
case, “double blinding” would not be a valid term. This may result
in false positive findings: if the trialist knows that a “positive” drug
was used and the study was an “equal effect test” study, there is
a potential risk that the outcome detectors will give same results
for the two groups. For example, the purpose of Chang 2005 was
to compare two different forms of the same drug; one was in a
granule form and the other was in a capsule form and the trialists
were aware of this. Therefore, there was a possibility that the
results were not scrutinised carefully - particularly the subjective
outcomes. In this case “double blinding” does not have any value.
We found that three trials claimed to have used ’double blinding’ (
Chang 2005; Chang 2007; Yang 2000) and one used ’single blinding’
(Chen 2004). These studies found a similar recovery rate as
the “positive” control. Two of the ’double blinding’ studies (Wang
2004; Wang 2008a) found the recovery rate in the intervention
group to be higher than the control group by almost 50% (Wang
2004 RR 1.43; Wang 2008a RR 1.59 and RR 1.67). However,
Wang 2004 lacked a description of how to verify the success of the
blinding. Another trial (Pan 2000) found the marked improvement
rate in the intervention group to be higher than the control
group (RR 1.69). For a disease like the common cold, which can
go into spontaneous remission within one week, it is very difficult
to find that the effect of a new drug is better than the “positive
effect” of the control drugs.We have to point out that the possible
reason that the relative risk is so high is that a high risk of selection
bias, detection bias or both may have existed in the studies where
the effects were similar or higher than “positive effect” controls.
Many trials incorrectly used drugs whose effects have not been
demonstrated as a control. Thus it is difficult to determine the
efficacy of the intervention by comparison.Where the intervention
is equal in efficacy to the control, no conclusion can be made.
For example, the average rate of recovery from the common cold
was the same for those participants taking Jinlian Qinre capsules
(intervention) and JinlianQinre granules (control) (Chang 2005).
Since there is no evidence assessing the efficacy of Jinlian Qinre
granules, we therefore cannot determine the efficacy of Jinlian
Qinre capsules.
Potential biases in the review process
We found the formulations of interventions in five studies (Ma
2000; Pan 2000; Yang 2000; Yu 1997; Yu 2005) were prepared
by either the trial authors or colleagues in their ho
