title: Internal validity of randomized controlled trials reported in major gastrointestinal and surgical endoscopy journals in 2008.
abstract: BACKGROUND
  Assessment of the reported methodology for randomized controlled trials (RCTs) in the major gastrointestinal and surgical endoscopy journals has never been reported.
  
  
  METHODS
  Generation of the allocation sequence, allocation concealment, double blinding, sample size calculation, number of patients, and funding source included in methodologic quality were retrieved from each trial, and all the relevant trials were identified by a search of all clinical trials published in 2008 in four major gastrointestinal and surgical endoscopy journals.
  
  
  RESULTS
  A total of 64 trials were included in the final analysis, which found that 50% (32/64) of all trials reported adequate generation of the allocation sequence, 58% (37/64) reported adequate allocation concealment, 47% (30/64) reported adequate blinding, 47% (30/64) reported adequate sample size calculation, and 67% (43/64) failed to disclose the funding source.
  
  
  CONCLUSIONS
  The study showed that the quality of the reported methodology in the major gastrointestinal and surgical endoscopy journals needs great improvement.
authors.affiliation: Department of Gastroenterology, Changhai Hospital, Second Military Medical University, 168 Changhai Road, Shanghai, China.
authors.forename: Yu
authors.initials: Y
authors.lastname: Bai
authors.forename: Yong-Fa
authors.initials: YF
authors.lastname: Wu
authors.forename: Dong
authors.initials: D
authors.lastname: Wang
authors.forename: Yang
authors.initials: Y
authors.lastname: Xia
authors.forename: Jun
authors.initials: J
authors.lastname: Gao
authors.forename: Duo-Wu
authors.initials: DW
authors.lastname: Zou
authors.forename: Zhao-Shen
authors.initials: ZS
authors.lastname: Li
mesh_terms: D004724:Endoscopy; D005762:Gastroenterology; D006801:Humans; D010506:Periodicals as Topic; D016032:Randomized Controlled Trials as Topic / Q000592:standards*; D012189:Retrospective Studies