Prospective registration, bias risk and outcome-reporting bias in randomised clinical trials of traditional Chinese medicine: an empirical methodological study.

BACKGROUND: Clinical trials on Traditional Chinese Medicine (TCM) should be registered in a publicly accessible international trial register and report on all outcomes. We systematically assessed and evaluated TCM trials in registries with their subsequent publications. OBJECTIVE: To describe the characteristics of TCM trials, estimate bias risk and outcome-reporting bias in clinical trials. DATA SOURCES AND STUDY SELECTION: Fifteen trial registries were searched from their inception to July 2012 to identify randomised trials on TCM including Chinese herbs, acupuncture and/or moxibustion, cupping, tuina, qigong, etc. DATA EXTRACTION: We extracted data including TCM specialty and treated disease/conditions from the registries and searched for subsequent publications in PubMed and Chinese databases. We compared information in the registries of completed trials with any publications focusing on study design, sample size, randomisation, bias risk including reporting bias from the register protocol. RESULTS: 1096 registered randomised trials were identified evaluating TCM, of which 505 were completed studies (46.1%). The most frequent conditions were pain (13.3%), musculoskeletal (11.7%), nervous (8.7%), digestive (7.1%), circulatory (6.5%), respiratory (6.3%), mental and behavioural disorders (6.2%) and cancer (6.0%). The trial register data identified parallel, phase II/III randomised trials with sample size estimations and blinding, but limited information about randomisation (sequence generation and allocation concealment). Comparing trial registration data of 115 completed trials (22.8%) with their subsequent 136 publications, inconsistencies were identified in one or more of the following: sample size (11%), outcome assessor blinding (37.5%), primary outcomes (29%) and safety (28%) reporting. CONCLUSIONS: Increasing numbers of clinical trials investigating a variety of TCM interventions have been registered in international trial registries. The study design of registered TCM trials has improved in estimating sample size, use of blinding and placebos. However, selective outcome reporting is widespread and similar to conventional medicine and therefore study conclusions should be interpreted with caution.

[Reporting specification of systematic reviews on Chinese medicine and methodological evaluation].

Currently, the number of systematic reviews on Chinese medicine (CM) increases gradually. However, the quality of the reviews varied, which resulted in great limitations in guiding clinical practice. This article refers to the Cochrane Handbook and PRISMA Statement to introduce the reporting specification of the systematic review, including asking a research question, review methods, presentation of the results, discussion and conclusion. We analyzed the methodology issues in the published systematic reviews on CM in order to improve the quality of future reviews.

[Using nested case-control study to appraise the effectiveness of Chinese medicines in the treatment of diabetic nephropathy].

OBJECTIVE: A nested case-control study was carried out to assess the effectiveness of Chinese medicines in the treatment of diabetic nephropathy, so as to explore the feasibility of using nested case-control study on effect assessment of Chinese medicine. METHODS: Nested case-control study was applied and the participants were enrolled from the subjects recruited in a cohort study. The cases and the controls were matched by 1 to 4 in age, gender, nationality and the stage of diabetic nephropathy when recruited in the cohort study. The EpiData 3.1 software was used for inputting data and SAS system was used for data analysis. Conditional logistic regress was applied to analyze the relationship between treatment and the progression of diabetic nephropathy. The study power was estimated and the sample sizes for case-control study and cohort study were recalculated based on the data from the cohort study. RESULTS: Eight cases and 32 controls were recruited in this study. The education level, ratio of drug withdrawal, change of therapy, syndrome differentiation and treatment were not significantly different in case and control groups. The progression of diabetic nephropathy was not significantly related with the treatment and the odds ratio (OR) value was 0.725 with a 95% confidence interval from 0.174 to 3.030. The statistical power of the study was 5%. To achieve the statistical power of 80%, 1 350 (270:1 080) participants were needed for 1:4 matched case-control study, 880 (440:440) for 1:1 paired case-control study, and 1 020 (510:510) for 1:1 control study. CONCLUSION: The treatment method is not significantly related with the progress of diabetic nephropathy. The nested case-control study is applicable in the therapeutic effect evaluation of Chinese medicine. Basic studies such as cross-sectional studies should be carried out to supply fundamental information for other types of studies including case-control study, cohort study and randomized clinical trials. Large sample size studies were needed to appraise the effect of Chinese medicine.