title: Reporting of noninferiority trials was incomplete in trial registries.
abstract: OBJECTIVE
  To examine the registration of noninferiority trials, with a focus on the reporting of study design and noninferiority margins.
  
  
  METHODS
  Cross-sectional study of registry records of noninferiority trials published from 2005 to 2009 and records of noninferiority trials in the International Standard Randomized Controlled Trial Number (ISRCTN) or ClinicalTrials.gov trial registries. The main outcome was the proportion of records that reported the noninferiority design and margin.
  
  
  RESULTS
  We analyzed 87 registry records of published noninferiority trials and 149 registry records describing noninferiority trials. Thirty-five (40%) of 87 records from published trials described the trial as a noninferiority trial; only two (2%) reported the noninferiority margin. Reporting of the noninferiority design was more frequent in the ISRCTN registry (13 of 18 records, 72%) compared with ClinicalTrials.gov (22 of 69 records, 32%; P=0.002). Among the 149 records identified in the registries, 13 (9%) reported the noninferiority margin. Only one of the industry-sponsored trial compared with 11 of the publicly funded trials reported the margin (P=0.001).
  
  
  CONCLUSIONS
  Most registry records of noninferiority trials do not mention the noninferiority design and do not include the noninferiority margin. The registration of noninferiority trials is unsatisfactory and must be improved.
authors: Department of Clinical Epidemiology, Leiden University Medical Centre, Albinusdreef 2, 2300 RC Leiden, The Netherlands. o.m.dekkers@lumc.nl
authors: Olaf M
authors: OM
authors: Dekkers
authors: Darius
authors: D
authors: Soonawala
authors: Jan P
authors: JP
authors: Vandenbroucke
authors: Matthias
authors: M
authors: Egger
mesh_terms: D015982:Bias; D002986:Clinical Trials as Topic / Q000706:statistics & numerical data*; D003430:Cross-Sectional Studies; D006801:Humans; D039781:PubMed; D011643:Publishing; D012042:Registries / Q000706:statistics & numerical data*; D012107:Research Design; D013810:Therapeutic Equivalency