Core Outcome Measures in Effectiveness Trials

Towards a core outcome set for clinical trials in headache (COSH): an international, multi-perspective initiative

General Information

Systematic reviews of headache clinical trials, outcome reporting and the quality and acceptability of PROMs used in the headache population – conducted as part of a larger clinical trial (the CHESS study (PI Prof Martin Underwood)) – have highlighted significant heterogeneity in outcome reporting in headache studies, raising concerns over reporting bias and limiting the conduct of systematic reviews and meta-analyses of evidence. An international, multi-stakeholder consensus on the most important outcomes to include in future clinical trials in the headache population – what to assess and how – is required, and will be addressed by the proposed study.

Principal investigator - Dr Kirstie Haywood. Royal College of Nursing Research Institute, Warwick Medical School, Warwick University.

Further Study Information

Current Stage:
January 2017 - January 2018
Funding source(s):

Health Area

Disease Category

Disease Name

Target Population

Age Range
18 - 100


Nature / type of Intervention


Consensus meeting
Delphi process
Literature review
Nominal group technique (NGT)
Systematic review

Three key stages are proposed:
1. A comprehensive list of outcomes will be developed to inform questionnaire development for the international e-Delphi.
a. This will be informed by systematic reviews completed as part of the CHESS study.
b. Qualitative research and narrative reviews completed as part of the CHESS study.
c. A long-list of potential outcomes will be considered, mapped onto health domains and discussed with key stakeholders, including patient research partners.
d. A final list of outcomes and domains will inform items for the e-Delphi (stage 2).

2. A three-round international e-Delphi survey is proposed to work towards consensus on the core domain set (CDS).
a. International participants will be identified – to reflect key stakeholders including health professionals, clinicians, patients, clinical academics, researchers.

3. An international, multi-stakeholder consensus meeting (modified nominal group) will be held to confirm the core domain set (CDS) and to achieve consensus on the core outcome measurement set (COMS).

Stakeholders Involved

Clinical experts
Consumers (patients)
Patient/ support group representatives
Service users

Study Type

COS for clinical trials or clinical research

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