title: Abstracts of randomized controlled trials presented at the society for pediatric research meeting: an example of publication bias.
abstract: BACKGROUND
  Publication bias toward studies that favor new therapies has been known to occur for the past 40 years, yet its implications are not well studied in child health. The increased interest in meta-analyses has highlighted the need to identify the totality of evidence when addressing treatment questions.
  
  
  OBJECTIVE
  To measure the percentage of randomized controlled trials (RCTs) presented at a major pediatric scientific meeting that were subsequently published as full-length articles, to investigate factors associated with publication, and to describe the variables that change from abstract to manuscript form.
  
  
  METHODS
  The scientific proceedings from the Society for Pediatric Research were hand searched for RCTs (1992-1995). Subsequent publication was ascertained through a search of various electronic databases. Quality of abstracts and manuscripts was measured, and data were extracted using a structured form.
  
  
  RESULTS
  A total of 264 (59.1%) of 447 abstracts were subsequently published. Almost 64% of RCTs that were subsequently published favored new therapy compared with 43.5% of studies that were never published (P<.001). Mean effect size for published vs unpublished RCTs was 0.74 vs 0.05 (P<.001). Median sample size was larger in published (n = 45) vs unpublished (n = 34) RCTs (P =.02). Quality was significantly lower for abstracts vs published RCTs (P<.001). For 5% of abstracts that were subsequently published, the conclusion regarding treatment efficacy changed.
  
  
  CONCLUSIONS
  Publication bias is a serious threat to assessing the effectiveness of interventions in child health, as little more than half of RCTs presented at a major scientific meeting are subsequently published. There is a need to institute an international registry of RCTs in children so that the totality of evidence can be accessed when assessing treatment effectiveness.
authors: Department of Pediatrics, University of Alberta, 2C3.67 Walter C. Mackenzie Centre, Edmonton, Alberta, Canada T6G 2B7. terry.klassen@ualberta.ca
authors: Terry P
authors: TP
authors: Klassen
authors: Natasha
authors: N
authors: Wiebe
authors: Kelly
authors: K
authors: Russell
authors: Kelly
authors: K
authors: Stevens
authors: Lisa
authors: L
authors: Hartling
authors: William R
authors: WR
authors: Craig
authors: David
authors: D
authors: Moher
mesh_terms: D002648:Child; D006801:Humans; D016015:Logistic Models; D010372:Pediatrics; D017594:Publication Bias; D016032:Randomized Controlled Trials as Topic; D013997:Time Factors