Clinically meaningful performance benchmarks in MS: timed 25-foot walk and the real world.

Abstract

Identify and validate clinically meaningful Timed 25-Foot Walk (T25FW) performance benchmarks in individuals living with multiple sclerosis (MS). Cross-sectional study of 159 MS patients first identified candidate T25FW benchmarks. To characterize the clinical meaningfulness of T25FW benchmarks, we ascertained their relationships to real-life anchors, functional independence, and physiologic measurements of gait and disease progression. Candidate T25FW benchmarks were then prospectively validated in 95 subjects using 13 measures of ambulation and cognition, patient-reported outcomes, and optical coherence tomography. T25FW of 6 to 7.99 seconds was associated with a change in occupation due to MS, occupational disability, walking with a cane, and needing "some help" with instrumental activities of daily living; T25FW ≥8 seconds was associated with collecting Supplemental Security Income and government health care, walking with a walker, and inability to do instrumental activities of daily living. During prospective benchmark validation, we trichotomized data by T25FW benchmarks (<6 seconds, 6-7.99 seconds, and ≥8 seconds) and found group main effects on 12 of 13 objective and subjective measures (p < 0.05). Using a cross-sectional design, we identified 2 clinically meaningful T25FW benchmarks of ≥6 seconds (6-7.99) and ≥8 seconds. Longitudinal and larger studies are needed to confirm the clinical utility and relevance of these proposed T25FW benchmarks and to parse out whether there are additional benchmarks in the lower (<6 seconds) and higher (>10 seconds) ranges of performance.