Reliability and validity of the European Portuguese version of the ABILHAND questionnaire in Patients with Systemic Sclerosis

Systemic sclerosis (SSc) frequently affects hands, impairing its function and impacting quality of life. The ABILHAND-SSc is a patient-reported outcome measure (PROM) specifically designed to assess manual ability in SSc. Previously, an European Portuguese version has been translated and culturally adapted, but its psychometric properties remain to be validated. Therefore, we aim to validate the European Portuguese version of the ABILHAND-SSc in patients with systemic sclerosis (SSc) using Rasch analysis and classical test theory. A cross-sectional validation study was conducted in a tertiary rheumatology centre, including 53 Portuguese-speaking adults fulfilling ACR/EULAR 2013 classification criteria for SSc or VEDOSS classification criteria. Patients completed the ABILHAND-SSc along with other PROMs: HAQ-DI, SHAQ, SF-36v2, EQ-5D-5L, and ScleroID. Rasch analysis assessed item fit, dimensionality, targeting, and reliability. Test-retest reliability was evaluated in a stable subsample. Construct validity was examined via hypothesis testing and correlation with external instruments. The ABILHAND-SSc showed excellent internal consistency and Rasch-based reliability. Item fit statistics were within acceptable ranges, and no floor or ceiling effects were observed. Rasch and PCA analyses supported unidimensionality. Test-retest reliability was good. ABILHAND-SSc scores showed good correlation with related PROMs. Patients with diffuse cutaneous SSc had significantly lower manual ability than those with VEDOSS. In conclusion, the European Portuguese version of the ABILHAND-SSc is a valid, reliable, and feasible tool for assessing manual ability in patients with SSc. Its use in clinical practice and research may support patient-centred assessment and monitoring of hand function. Further validation in longitudinal and multicentre studies is warranted.