Article type
Year
Abstract
Background: Randomised controlled trials (RCTs) can provide potent evidence for efficacy of health-care interventions. However, trials of low methodological quality cause over- or under-estimation of treatment effect and influence results and conclusions of systematic reviews. Chinese medicinal herbs which have particular drug types, color and smells make the control of methodological quality even harder. At present, 11 RCTs to the year 2004 have been included in the Cochrane systematic review of Chinese medicinal herbs for influenza.
Objectives: To determine the methodological quality of RCTs included in the review of Chinese medicinal herbs for influenza.
Methodology: The quality reporting of each trial was assessed based largely on as described by Cochrane Reviewers Handbook 4.2.2. In particular, the following factors including generation of allocation sequence, allocation concealment, double blinding, and follow-up were evaluated to determine whether they were adequate or inadequate. Based on these criteria, studies were broadly subdivided into the following three categories: A - all quality criteria met: low risk of bias. B - one or more of the quality criteria only partly met: moderate risk of bias. C - one or more criteria not met: high risk of bias. Two reviewers assessed each trial independently.
Results: Most of the 11 included trials were of low quality (C) except three with relative higher quality (A). All of the studies mentioned randomisation allocation. However, only one mentioned the methods of randomisation and none mentioned allocation concealment. Only one study mentioned double-blinding, 8 didn't use blinding because of different administration formulation in comparison groups, and whether blinding was used is unclear in two studies. None of the included studies mentioned dropouts or performed an intention-to-treat analysis.
Conclusions: Most of the RCTs are poor in methodological quality which may be due to poor reporting and/or failure in design. Continued efforts are required to improve both methodological and reporting quality of the design and execution of RCTs in this field. Drug types, color and smells of Chinese medicinal herbs should be modified so that double blinding is available.
Objectives: To determine the methodological quality of RCTs included in the review of Chinese medicinal herbs for influenza.
Methodology: The quality reporting of each trial was assessed based largely on as described by Cochrane Reviewers Handbook 4.2.2. In particular, the following factors including generation of allocation sequence, allocation concealment, double blinding, and follow-up were evaluated to determine whether they were adequate or inadequate. Based on these criteria, studies were broadly subdivided into the following three categories: A - all quality criteria met: low risk of bias. B - one or more of the quality criteria only partly met: moderate risk of bias. C - one or more criteria not met: high risk of bias. Two reviewers assessed each trial independently.
Results: Most of the 11 included trials were of low quality (C) except three with relative higher quality (A). All of the studies mentioned randomisation allocation. However, only one mentioned the methods of randomisation and none mentioned allocation concealment. Only one study mentioned double-blinding, 8 didn't use blinding because of different administration formulation in comparison groups, and whether blinding was used is unclear in two studies. None of the included studies mentioned dropouts or performed an intention-to-treat analysis.
Conclusions: Most of the RCTs are poor in methodological quality which may be due to poor reporting and/or failure in design. Continued efforts are required to improve both methodological and reporting quality of the design and execution of RCTs in this field. Drug types, color and smells of Chinese medicinal herbs should be modified so that double blinding is available.