Defining domains: developing consensus-based definitions for foundational domains in OMERACT core outcome sets.

Area of Science:

• Rheumatology
• Outcomes Research
• Measurement Science

Background:

• Outcome Measures in Rheumatology (OMERACT) utilizes core domain sets for clinical trials.
• Standardized definitions are crucial for consistent data collection and interpretation in rheumatology outcomes research.

Purpose of the Study:

• To develop detailed, consensus-based definitions for foundational domains within OMERACT core domain sets.
• To enhance the clarity and consistency of outcome measures used in rheumatology research.

Main Methods:

• Systematic identification of candidate domain definitions from existing literature and organizational guidelines.
• Two-round Delphi survey administered to OMERACT working groups, patient research partners, and the Technical Advisory Group.
• Consensus-building discussions and contextualization of definitions using lived experience at the OMERACT 2023 Methodology Workshop.

Main Results:

• Consensus was reached on detailed definitions for five foundational domains: pain intensity, pain interference, physical function, fatigue, and health-related quality of life.
• A preferred definition for patient global assessment could not be established, indicating a need for further research.
• Lived experience examples were incorporated to contextualize the finalized domain definitions.

Conclusions:

• A consensus-based approach successfully yielded detailed definitions for five key OMERACT domains.
• These standardized definitions aim to streamline the instrument selection process and reduce resource requirements for future OMERACT core outcome set development.
• Further research is necessary to establish a consensus definition for patient global assessment.