title: Reporting of methodologic information on trial registries for quality assessment: a study of trial records retrieved from the WHO search portal.
abstract: BACKGROUND
  Although randomized clinical trials (RCTs) are considered the gold standard of evidence, their reporting is often suboptimal. Trial registries have the potential to contribute important methodologic information for critical appraisal of study results.
  
  
  RESULTS
  The objective of the study was to evaluate the reporting of key methodologic study characteristics in trial registries. We identified a random sample (n = 265) of actively recruiting RCTs using the World Health Organization International Clinical Trials Registry Platform (ICTRP) search portal in 2008. We assessed the reporting of relevant domains from the Cochrane Collaboration's 'Risk of bias' tool and other key methodological aspects. Our primary outcomes were the proportion of registry records with adequate reporting of random sequence generation, allocation concealment, blinding, and trial outcomes. Two reviewers independently assessed each record. Weighted overall proportions in the ICTRP search portal for adequate reporting of sequence generation, allocation concealment, blinding (including and excluding open label RCT) and primary outcomes were 5.7% (95% CI 3.0-8.4%), 1.4% (0-2.8%), 41% (35-47%), 8.4% (4.1-13%), and 66% (60-72%), respectively. The proportion of adequately reported RCTs was higher for registries that used specific methodological fields for describing methods of randomization and allocation concealment compared to registries that did not. Concerning other key methodological aspects, weighted overall proportions of RCTs with adequately reported items were as follows: eligibility criteria (81%), secondary outcomes (46%), harm (5%) follow-up duration (62%), description of the interventions (53%) and sample size calculation (1%).
  
  
  CONCLUSIONS
  Trial registries currently contain limited methodologic information about registered RCTs. In order to permit adequate critical appraisal of trial results reported in journals and registries, trial registries should consider requesting details on key RCT methods to complement journal publications. Full protocols remain the most comprehensive source of methodologic information and should be made publicly available.
authors.affiliation: Research Institute, Sanitas University Foundation, Bogotá, Colombia. lreveiz@yahoo.com
authors.forename: Ludovic
authors.initials: L
authors.lastname: Reveiz
authors.forename: An-Wen
authors.initials: AW
authors.lastname: Chan
authors.forename: Karmela
authors.initials: K
authors.lastname: Krleza-Jerić
authors.forename: Carlos Eduardo
authors.initials: CE
authors.lastname: Granados
authors.forename: Mariona
authors.initials: M
authors.lastname: Pinart
authors.forename: Itziar
authors.initials: I
authors.lastname: Etxeandia
authors.forename: Diego
authors.initials: D
authors.lastname: Rada
authors.forename: Monserrat
authors.initials: M
authors.lastname: Martinez
authors.forename: Xavier
authors.initials: X
authors.lastname: Bonfill
authors.forename: Andrés Felipe
authors.initials: AF
authors.lastname: Cardona
mesh_terms: D006801:Humans; D016247:Information Storage and Retrieval / Q000379:methods*; D011786:Quality Control; D016032:Randomized Controlled Trials as Topic / Q000592:standards; D012042:Registries; D012107:Research Design / Q000592:standards*; D014944:World Health Organization
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