Convergent validity of the Functional Bridge Test and its prognostic association with walking independence in patients with acute stroke: a retrospective cohort study

BACKGROUND: The Functional Bridge Test (FBT) is a simple bedside assessment tool for evaluating hip elevation. It has demonstrated good validity and reliability in patients with lower limb hemiplegia after stroke and is significantly associated with stroke severity, lower limb strength, and basic mobility. However, its applicability across all patients with acute stroke, including those without lower limb hemiparesis, has not yet been established. OBJECTIVES: This study aimed to examine the convergent validity of the FBT and its prognostic association with walking independence in patients with acute stroke. METHODS: This study included consecutive patients with acute stroke admitted to a university hospital who survived and had complete data for outcome assessment. Convergent validity was evaluated using the National Institutes of Health Stroke Scale (NIHSS) total score, the NIHSS motor leg subscore on the affected side, and the Functional Status Score for the Intensive Care Unit (FSS-ICU), all measured on the first day of the rehabilitation program. The association between FBT grade and walking independence at a variable discharge-based endpoint, defined as the end of the inpatient rehabilitation program, was assessed through unadjusted and adjusted logistic regression analyses. CONCLUSIONS: The FBT demonstrated adequate convergent validity and prognostic association in patients with acute stroke. This practical bedside assessment was associated with early functional status and walking independence at a variable discharge-based endpoint. Further prospective validation using standardized follow-up time points is needed.