The Measurement Properties and Applications of WHODAS 2.0 in Multiple Sclerosis: A Systematic Review.

Background/Objectives: Multiple sclerosis (MS) affects motor, cognitive, psychological, and social functioning that impairment-based scales do not fully capture. This systematic review evaluated the measurement properties and applications of the World Health Organization Disability Assessment Schedule (WHODAS) 2.0 in adults with MS across research and clinical contexts. Methods: PubMed/MEDLINE, Embase, Scopus, Web of Science, and the Cochrane Library were searched from inception to 25 May 2026. Eligible peer-reviewed studies reported extractable WHODAS data in adults with MS. Evidence was organized into measurement, clinical-association, participation/employment, intervention, digital-monitoring, and longitudinal streams. Design-appropriate critical-appraisal tools and outcome-specific certainty assessments were applied; quantitative pooling was assessed but was not justified. Results: Of the 677 records identified, 28 reports were included. Five reports evaluated measurement properties; moderate-certainty evidence supported reliability and construct validity, although precision differed among 12-, 32-, and 36-item forms. Associations with quality of life and clinical severity were supported by low-certainty evidence. Evidence concerning fatigue, mood, cognition, participation, and employment was of low or very low certainty because most studies were cross-sectional, used heterogeneous metrics, or involved overlapping cohorts. Intervention evidence was of very low to low certainty: WHODAS was secondary, and interventions, time points, and scoring methods were not comparable. Eight reports arose from one overlapping research program. Conclusions: WHODAS 2.0 provides a multidimensional patient-reported account of functioning in MS and may complement, but not replace, the Expanded Disability Status Scale. Evidence supports measurement use more strongly than prognostic, treatment-response, or benefit-determination claims. Standardized version selection, scoring, domain reporting, and prespecified longitudinal endpoints are required.