Outcome measurement instruments for adult brachial plexus injury: a systematic review of development and measurement properties

To review candidate outcome measurement instruments (OMIs) for the core outcome set (COS) for brachial plexus injury (BPI) and identify those with the strongest measurement properties. We conducted a PRISMA-compliant systematic review to identify studies on the measurement properties of domain-specific OMIs for adult BPI. OMIs with adequate content validity were further evaluated. Two independent reviewers assessed the methodological quality of each study using the COSMIN Risk of Bias checklist and assessed overall quality using a modified GRADE approach. Nineteen development/validation studies concerning nine OMIs were identified. The Brachial Assessment Tool (BrAT) and the Impact of Brachial Plexus Injury Questionnaire (IMBPIQ) (both measuring carrying out daily routine) had sufficient content validity to proceed to full evaluation. The BrAT had moderate quality evidence to support its psychometric properties. The IMBPIQ needs further research to evidence structural validity and internal consistency. The Brief Pain Inventory has strong psychometric properties in other populations and is recommended for the core measurement set (CMS) for chronic pain. The BrAT and the Brief Pain Inventory are recommended for inclusion in the BPI CMS. Further consensus work is needed to identify the most appropriate OMI for voluntary movement. Systematic Review Registration: PROSPERO (CRD42022307564). The Brachial Assessment Tool and the Brief Pain Inventory are recommended as outcome measurement instruments to assess two of the three core domains from the brachial plexus injury (BPI) core outcome set.Further consensus work is needed to agree appropriate measures for voluntary movement.These recommendations will facilitate evidence synthesis in adult BPI studies, by reducing measurement heterogeneity, thus improving the quality of evidence to inform best patient care. The Brachial Assessment Tool and the Brief Pain Inventory are recommended as outcome measurement instruments to assess two of the three core domains from the brachial plexus injury (BPI) core outcome set. Further consensus work is needed to agree appropriate measures for voluntary movement. These recommendations will facilitate evidence synthesis in adult BPI studies, by reducing measurement heterogeneity, thus improving the quality of evidence to inform best patient care.