title: Prospective registration, bias risk and outcome-reporting bias in randomised clinical trials of traditional Chinese medicine: an empirical methodological study.
abstract: 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.
  
  
  METHODS
  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.
  
  
  METHODS
  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.
authors.affiliation: Centre for Evidence-Based Chinese Medicine, Beijing University of Chinese Medicine, Beijing, China.
authors.forename: Jian-Ping
authors.initials: JP
authors.lastname: Liu
authors.forename: Mei
authors.initials: M
authors.lastname: Han
authors.forename: Xin-Xue
authors.initials: XX
authors.lastname: Li
authors.forename: Yu-Jie
authors.initials: YJ
authors.lastname: Mu
authors.forename: George
authors.initials: G
authors.lastname: Lewith
authors.forename: Yu-Yi
authors.initials: YY
authors.lastname: Wang
authors.forename: Claudia M
authors.initials: CM
authors.lastname: Witt
authors.forename: Guo-Yan
authors.initials: GY
authors.lastname: Yang
authors.forename: Eric
authors.initials: E
authors.lastname: Manheimer
authors.forename: Torkel
authors.initials: T
authors.lastname: Snellingen
authors.forename: Brian
authors.initials: B
authors.lastname: Berman
authors.forename: Christian
authors.initials: C
authors.lastname: Gluud