A Core Outcome Set for Preventive Intervention Trials in Chronic and Episodic Migraine (COSMIG): an international, consensus-derived and multistakeholder initiative

CHESS COSMIG group, Kirstie L Haywood, Rachel Potter, Robert Froud, Gemma Pearce, Barbara Box, Richard Lipton, Stavros Petrou, Regina Rendas-Baum, Anne-Marie Logan, Kimberley Stewart, Martin Underwood, Manjit M Matharu

Research output: Contribution to journalArticlepeer-review

20 Citations (Scopus)
46 Downloads (Pure)


Typically, migraine prevention trials focus on reducing migraine days. This narrow focus may not capture all that is important to people with migraine. Inconsistency in outcome selection across trials limits the potential for data pooling and evidence synthesis. In response, we describe the development of core outcome set for migraine (COSMIG).Design:
A two-stage approach sought to achieve international, multistakeholder consensus on both the core domain set and core measurement set. Following construction of a comprehensive list of outcomes, expert panellists (patients, healthcare professionals and researchers) completed a three-round electronic-Delphi study to support a reduction and prioritisation of core domains and outcomes. Participants in a consensus meeting finalised the core domains and methods of assessment. All stages were overseen by an international core team, including patient research partners.Results:
There was a good representation of patients (episodic migraine (n=34) and chronic migraine (n=42)) and healthcare professionals (n=33) with high response and retention rates. The initial list of domains and outcomes was reduced from >50 to 7 core domains for consideration in the consensus meeting, during which a 2-domain core outcome set was agreed.Conclusion: International and multistakeholder consensus emerged to describe a two-domain core outcome set for reporting research on preventive interventions for chronic and episodic migraine: migraine-specific pain and migraine-specific quality of life. Intensity of migraine pain assessed with an 11-point Numerical Rating Scale and the frequency as the number of headache/migraine days over a specified time period. Migraine-specific quality of life assessed using the Migraine Functional Impact Questionnaire.
Original languageEnglish
Article numbere043242
Pages (from-to)e043242
JournalBMJ Open
Issue number11
Publication statusPublished - 30 Nov 2021

Bibliographical note

© Author(s) (or their employer(s)) 2021. Re-use permitted under CC BY. Published by BMJ. https://creativecommons.org/licenses/by/4.0/This is an open access article distributed in accordance with the Creative Commons Attribution 4.0 Unported (CC BY 4.0) license, which permits others to copy, redistribute, remix, transform and build upon this work for any purpose, provided the original work is properly cited, a link to the licence is given, and indication of whether changes were made. See: https://creativecommons.org/licenses/by/4.0/.


  • clinical trials
  • migraine
  • statistics & research methods

ASJC Scopus subject areas

  • Medicine(all)


Dive into the research topics of 'A Core Outcome Set for Preventive Intervention Trials in Chronic and Episodic Migraine (COSMIG): an international, consensus-derived and multistakeholder initiative'. Together they form a unique fingerprint.

Cite this