title: Placebo-controlled trials of Chinese herbal medicine and conventional medicine comparative study.
abstract: BACKGROUND
  Chinese herbal medicine (CHM) is increasingly used in the West, but the evidence on its effectiveness is a matter of debate. We compared the characteristics, study quality and results of clinical trials of CHM and conventional medicine.
  
  
  METHODS
  Comparative study of placebo-controlled trials of CHM and conventional medicine. Eleven bibliographic databases and searches by hand of 48 Chinese-language journals. Conventional medicine trials matched for condition and type of outcome were randomly selected from the Cochrane Controlled Trials Register (issue 1, 2003). Trials described as double-blind, with adequate generation of allocation sequence and adequate concealment of allocation, were assumed to be of high quality. Data were analysed using funnel plots and multivariable meta-regression models.
  
  
  RESULTS
  136 CHM trials (119 published in Chinese, 17 published in English) and 136 matched conventional medicine trials (125 published in English) were analysed. The quality of Chinese-language CHM trials tended to be lower than that of English-language CHM trials and conventional medicine trials. Three (2%) CHM trials and 10 (7%) conventional medicine trials were of high quality. In all groups, smaller trials showed more beneficial treatment effects than larger trials. CHM trials published in Chinese showed considerably larger effects than CHM trials published in English (adjusted ratio of ORs 0.29, 95% confidence intervals 0.17-0.52).
  
  
  CONCLUSIONS
  Biases are present both in placebo-controlled trials of CHM and conventional medicine, but may be most pronounced in CHM trials published in Chinese-language journals. Only few CHM trials of adequate methodology exist and the effectiveness of CHM therefore remains poorly documented.
authors.affiliation: Institute of Social and Preventive Medicine (ISPM), University of Berne, Switzerland.
authors.forename: Aijing
authors.initials: A
authors.lastname: Shang
authors.forename: Karin
authors.initials: K
authors.lastname: Huwiler
authors.forename: Linda
authors.initials: L
authors.lastname: Nartey
authors.forename: Peter
authors.initials: P
authors.lastname: Jüni
authors.forename: Matthias
authors.initials: M
authors.lastname: Egger
mesh_terms: D015982:Bias; D018849:Controlled Clinical Trials as Topic / Q000592:standards; D004365:Drugs, Chinese Herbal / Q000627:therapeutic use; D006801:Humans; D007802:Language; D008516:Medicine, Chinese Traditional; D008517:Phytotherapy; D011643:Publishing; D012107:Research Design / Q000592:standards; D016896:Treatment Outcome
chemical_list: D004365:Drugs, Chinese Herbal