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Protocol for developing, disseminating and implementing a core outcome set for endometriosis
  1. Martin Hirsch1,
  2. James M N Duffy2,
  3. Claire Barker3,
  4. Lone Hummelshoj4,5,
  5. Neil P Johnson4,6,
  6. Ben Mol6,
  7. Khalid S Khan1,
  8. Cindy Farquhar7
  9. On behalf of the International Collaboration to Harmonize Outcomes and Measures for Endometriosis (iHOME)
  1. 1Women's Health Research Unit, Barts and the London School of Medicine and Dentistry, London, UK
  2. 2Balliol College, University of Oxford, Oxford, UK
  3. 3Radcliffe Women's Health Patient Participation Group, University of Oxford, Oxford, UK
  4. 4World Endometriosis Society, Vancouver, British Columbia, Canada
  5. 5World Endometriosis Research Foundation, London, UK
  6. 6Robinson Research Institute, University of Adelaide, Adelaide, South Australia, Australia
  7. 7Cochrane Gynaecology and Fertility Group, University of Auckland, Auckland, New Zealand
  1. Correspondence to Dr Martin Hirsch; m.hirsch{at}


Introduction Endometriosis is a common gynaecological disease characterised by pain and subfertility. Randomised controlled trials evaluating treatments for endometriosis have reported many different outcomes and outcome measures. This variation restricts effective data synthesis limiting the usefulness of research to inform clinical practice. To address these methodological concerns, we aim to develop, disseminate and implement a core outcome set for endometriosis engaging with key stakeholders, including healthcare professionals, researchers and women with endometriosis.

Methods and analysis An international steering group has been established, including healthcare professionals, researchers and patient representatives. Potential outcomes identified from a systematic review of the literature will be entered into a modified Delphi method. Key stakeholders will be invited to participate including healthcare professionals, researchers and women with endometriosis. Participants will be invited to score individual outcomes on a nine-point Likert scale anchored between 1 (not important) and 9 (critical). Repeated reflection and rescoring should promote whole and individual stakeholder group converge towards consensus, ‘core’, outcomes. High-quality outcome measures will be associated with core outcomes.

Ethics and dissemination The implementation of a core outcome set for endometriosis within future clinical trials, systematic reviews and clinical guidelines will enhance the availability of comparable data to facilitate evidence-based patient care. This study was prospectively registered with Core Outcome Measures in Effectiveness Trials Initiative; number: 691.

  • Core outcome sets
  • Consensus methodology
  • Endometriosis
  • outcome harmonization
  • Outcome variation

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  • Funding This study is funded by the Endometriosis Millennium Fund, Royal College of Obstetricians and Gynaecologists. The funder has no role in the design and conduct of the study, the collection, management, analysis, or interpretation of data, or manuscript preparation.

  • Collaborators International Collaboration to Harmonise Outcomes and Measures for Endometriosis (iHOME).

  • Contributors MH, JMND and KSK have been involved with the study's conception and design. MH, JMND, CB, LH, BM, NPJ, KSK and CF will be involved in the acquisition, analysis and interpretation of data and will provide administrative, technical or material support. MH, JMND, KSK, NPJ and CF will be involved in the statistical analysis. MH and JMND have drafted the manuscript. All authors have critically revised the manuscript for important intellectual content. All authors have read and approved the manuscript.

  • Competing interests NPJ has received conference expenses from Bayer Pharma, Merck-Serono and MSD; research funding from AbbVie and has been a consultant to Vifor Pharma. The remaining authors report no competing interests.

  • Provenance and peer review Not commissioned; externally peer reviewed.