Psychometric Validation of the Hemophilia Functional Ability Scoring Tool (Hemo-FAST)

The Hemophilia Functional Ability Scoring Tool (Hemo-FAST), consisting of a patient-reported outcome (PRO) part and a clinician-reported outcome (ClinRO) part, was developed as a rapid and effective tool to assess functional mobility in clinical practice. This study (NCT04731701) aimed to validate the psychometric properties of Hemo-FAST for assessment of joint health in people with haemophilia (PwH).PwH A or B aged ≥18 years completed questionnaires including the PRO part of Hemo-FAST and the short-form 36 health survey (SF-36) during one study visit. Clinicians completed the Haemophilia Joint Health Score (HJHS) and the ClinRO part of Hemo-FAST at the same visit. Validation was performed using reliability, construct validity, and structure validity assessments.The study enrolled 180 PwH A or B from 14 centres across France. Estimated time to complete the PRO part was mean (standard deviation) 4.6 (5.4) minutes. PRO items showed good test-retest reliability (intraclass correlation coefficient value ≥0.70). Inter-rater values were >0.70 for 7/9 ClinRO items, indicating good reliability. All items (15 PRO; 9 ClinRO) had high internal consistency (Cronbach's coefficient alpha: 0.97). Hemo-FAST demonstrated convergent construct validity with HJHS and the SF-36 physical component and discriminant construct validity with the SF-36 mental health component. Hemo-FAST scores distinguished between subgroups of people with expected differences in joint health status, including by haemophilia severity (p < 0.0001).This study successfully validated Hemo-FAST as a rapid and reliable tool for the functional assessment of joint health in adults with haemophilia, both in clinical practice and clinical research settings.