title: Variation in outcome reporting in endometriosis trials: a systematic review.
abstract: OBJECTIVE
  We reviewed the outcomes and outcome measures reported in randomized controlled trials and their relationship with methodological quality, year of publication, commercial funding, and journal impact factor.
  
  
  METHODS
  We searched the following sources: (1) Cochrane Central Register of Controlled Trials, (2) Embase, and (3) MEDLINE from inception to November 2014.
  
  
  METHODS
  We included all randomized controlled trials evaluating a surgical intervention with or without a medical adjuvant therapy for the treatment of endometriosis symptoms.
  
  
  METHODS
  Two authors independently selected trials, assessed methodological quality (Jadad score; range, 1-5), outcome reporting quality (Management of Otitis Media with Effusion in Cleft Palate criteria; range, 1-6), year of publication, impact factor in the year of publication, and commercial funding (yes or no). Univariate and bivariate analyses were performed using Spearman Rh and Mann-Whitney U tests. We used a multivariate linear regression model to assess relationship associations between outcome reporting quality and other variables.
  
  
  RESULTS
  There were 54 randomized controlled trials (5427 participants), which reported 164 outcomes and 113 outcome measures. The 3 most commonly reported primary outcomes were dysmenorrhea (10 outcome measures; 23 trials), dyspareunia (11 outcome measures; 21 trials), and pregnancy (3 outcome measures; 26 trials). The median quality of outcome reporting was 3 (interquartile range 4-2) and methodological quality 3 (interquartile range 5-2). Multivariate linear regression demonstrated a relationship between outcome reporting quality with methodological quality (β = 0.325; P = .038) and year of publication (β = 0.067; P = .040). No relationship was demonstrated between outcome reporting quality with journal impact factor (Rho = 0.190; P = .212) or commercial funding (P = .370).
  
  
  CONCLUSIONS
  Variation in outcome reporting within published endometriosis trials prohibits comparison, combination, and synthesis of data. This limits the usefulness of research to inform clinical practice, enhance patient care, and improve patient outcomes. In the absence of a core outcome set for endometriosis we recommend the use of the 3 most common pain (dysmenorrhea, dyspareunia, and pelvic pain) and subfertility (pregnancy, miscarriage, and live birth) outcomes. International consensus among stakeholders is needed to establish a core outcome set for endometriosis trials.
authors.affiliation: Women's Health Research Unit, Barts and The London School of Medicine and Dentistry, Whitechapel, London, United Kingdom. Electronic address: m.hirsch@qmul.ac.uk.
authors.forename: Martin
authors.initials: M
authors.lastname: Hirsch
authors.affiliation: Balliol College, University of Oxford, Oxford, United Kingdom.
authors.forename: James M N
authors.initials: JMN
authors.lastname: Duffy
authors.affiliation: Women's Health Research Unit, Barts and The London School of Medicine and Dentistry, Whitechapel, London, United Kingdom.
authors.forename: Jennie O
authors.initials: JO
authors.lastname: Kusznir
authors.affiliation: Women's Health Research Unit, Barts and The London School of Medicine and Dentistry, Whitechapel, London, United Kingdom.
authors.forename: Colin J
authors.initials: CJ
authors.lastname: Davis
authors.affiliation: Madrid Cochrane Collaboration Centre, Francisco de Vitoria University, Madrid, Spain; Clinical Biostatistics Unit, Ramon y Cajal Institute of Research and Centro de Investigación Biomédica en Red Epidemiology and Public Health, Madrid, Spain.
authors.forename: Maria N
authors.initials: MN
authors.lastname: Plana
authors.affiliation: Women's Health Research Unit, Barts and The London School of Medicine and Dentistry, Whitechapel, London, United Kingdom.
authors.forename: Khalid S
authors.initials: KS
authors.lastname: Khan
mesh_terms: D004412:Dysmenorrhea / Q000628:therapy; D004414:Dyspareunia / Q000628:therapy; D004715:Endometriosis / Q000628:therapy*; D005260:Female; D006801:Humans; D015999:Multivariate Analysis; D063868:Patient Outcome Assessment; D011247:Pregnancy; D016032:Randomized Controlled Trials as Topic / Q000592:standards*
keywords: core-outcome sets; endometriosis; outcome harmonization; outcome variation