Outcome measures monitoring physical function in children with haemophilia: a systematic review

Our objective was to provide a synthesis of measurement properties for performance-based outcome measures used to evaluate physical function in children with haemophilia. A systematic review of articles published in English using Medline, PEDro, Cinahl and The Cochrane Library electronic databases was conducted. Studies were included if a performance-based method, clinical evaluation or measurement tool was used to record an aspect of physical function in patients with haemophilia aged ≤ 18 years. Recording of self-perceived or patient-reported physical performance, abstracts, unpublished reports, case series reports and studies where the outcome measure was not documented or cross-referenced was excluded. Description of outcome measures, patient characteristics, measurement properties for construct validity, internal consistency, repeatability, responsiveness and feasibility was extracted. Data synthesis of 41 studies evaluating 14 measures is reported. None of the outcome measures demonstrated the requirements for all the measurement properties. Data on validity and test-retest repeatability were most lacking together with studies of sufficient size. Measurement of walking and muscle strength demonstrated good repeatability and discriminative properties; however, correlation with other measures of musculoskeletal impairment requires investigation. The Haemophilia Joint Health Score demonstrated acceptable construct validity, internal consistency and repeatability, but the ability to discriminate changes in physical function is still to be determined. Rigorous evaluation of the measurement properties of performance-based outcome measures used to monitor physical function of children with haemophilia in larger collaborative studies is required.