When the Patient-Reported Outcome Measure Probably Does Not Measure What You Think You Are Measuring: Quantifying Fear Avoidance Behaviours in people with Concussion. A COSMIN-Informed Systematic Review.

The validity of existing fear avoidance behaviour patient reported outcome measures (PROMs) for concussion is unknown. This study aims to (1) identify PROMs that assess fear avoidance behaviour in individuals with concussion and (2) assess the measurement properties of these PROMs. A systematic review of outcome measurement instruments using the Consensus Standards for the Selection of Health Measurement Instruments (COSMIN) checklist We performed a systematic search of seven databases. Studies were included if they assessed fear avoidance behaviour (e.g., kinesiophobia or cogniphobia) in participants with concussion, occurring in all settings (e.g., sport, falls, assaults). Methodological quality of the PROMs was assessed using the COSMIN checklist and the certainty of the evidence was assessed using the Grading of Recommendations Assessment, Development and Evaluation (GRADE) approach. We identified 40 studies assessing fear avoidance. Four studies (n=875 participants, representing three PROMs) were eligible for COSMIN assessment. Content validity for all PROMs was insufficient due to extreme risk of bias. The Fear Avoidance Short Form Scale demonstrated the greatest validity: moderate-certainty evidence for sufficient structural validity and internal consistency, and low-certainty evidence for measurement invariance. : Current PROMs for measuring fear avoidance behaviours in people with concussion have insufficient content validity, and should be used with caution in research and clinical practice.