title: Participation in clinical trials improves outcomes in women's health: a systematic review and meta-analysis.
abstract: BACKGROUND
  Previous reviews examining the effect of participation in trials on outcomes have not consistently shown benefit. Obstetrics and gynaecology is a unique disease area posing challenges for both researchers and patients.
  
  
  OBJECTIVE
  To determine whether participation in randomised controlled trials (RCTs), compared with non-participation, has a beneficial effect on women's health.
  
  
  METHODS
  Medline, Embase, the Cochrane Library, and PsycInfo were searched up to December 2015.
  
  
  METHODS
  We selected studies that reported the same clinical outcomes for participants in a women's health RCT and a comparable non-participant cohort.
  
  
  METHODS
  Data were extracted on quality, characteristics and study results. Outcomes were compared using logistic regression.
  
  
  RESULTS
  There were 21 relevant studies (20 160 women, 4759 outcome events). Trial participants, compared with non-participants, had 25% better odds of improved outcomes on average (OR 0.75; 95% CI 0.64-0.87; I2= 64.3%). The beneficial effect of participating in a trial was larger in comparisons where: RCTs were of high quality (OR 0.62; 95% CI 0.50-0.76) versus low (OR 0.92; 95% CI 0.74-1.16); and RCT intervention was not available to non-participants (OR 0.57; 95% CI 0.47-0.69) versus when it was (OR 1.13; 95% CI 0.89-1.44). The effect of trial participation was not influenced by effect size within the RCT (P = 0.48), whether funding was received or not (P = 0.13), whether non-participants received any treatment or not (P = 0.49), and the quality of the comparison of RCT participants with non-participants (P = 0.88).
  
  
  CONCLUSIONS
  Women participating in RCTs on average experienced better outcomes compared with those outside trials.
  
  
  CONCLUSIONS
  Participants in obstetric and gynaecology RCTs experience better outcomes compared with non-participants.
authors.affiliation: Women's Health Research Unit, Centre for Primary Care and Public Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, London, UK.
authors.forename: S K
authors.initials: SK
authors.lastname: Nijjar
authors.affiliation: Women's Health Research Unit, Centre for Primary Care and Public Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, London, UK.
authors.forename: M I
authors.initials: MI
authors.lastname: D'Amico
authors.affiliation: The London School of Medicine and Dentistry, London, UK.
authors.forename: N A
authors.initials: NA
authors.lastname: Wimalaweera
authors.affiliation: Women's Health Research Unit, Centre for Primary Care and Public Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, London, UK.
authors.forename: Nam
authors.initials: N
authors.lastname: Cooper
authors.affiliation: Women's Health Research Unit, Centre for Primary Care and Public Health, Blizard Institute, Barts and The London School of Medicine and Dentistry, London, UK.|Clinical Biostatistics Unit, Hospital Ramon y Cajal (IRYCIS) and CIBER Epidemiologia y Salud Publica, Madrid, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Zamora
authors.affiliation: Multidisciplinary Evidence Synthesis Hub (mEsh), Barts and the London School of Medicine and Dentistry, Queen Mary University, London, UK.
authors.forename: K S
authors.initials: KS
authors.lastname: Khan
mesh_terms: D005260:Female; D006801:Humans; D063868:Patient Outcome Assessment; D016032:Randomized Controlled Trials as Topic / Q000706:statistics & numerical data*; D035842:Research Subjects / Q000706:statistics & numerical data*; D016387:Women's Health / Q000706:statistics & numerical data*
keywords: Neonate; randomised; systematic review; trial participation; women's health