Establishing the Minimal Clinically Important Difference (MCID) for Smartphone-Derived Gait Measures in Multiple Sclerosis

2026-06-26

AI Summary

This study addresses the absence of minimally clinically important difference (MCID) thresholds for smartphone-derived gait metrics in multiple sclerosis (MS), which hinders the differentiation between day-to-day variability and true disease progression. Leveraging longitudinal data from the phase III CONSONANCE clinical trial, the authors employed an anchor-based approach integrated with multidimensional clinical scales to analyze gait parameters extracted from remote, smartphone-administered two-minute walk tests. For the first time, MCID values were established for six digital gait outcomes in MS patients: gait speed (−0.16 m/s), time-corrected gait speed (−0.18 m/s), step time (+0.06 s), step length (−0.07 m), total steps (−28), and total distance (−24 m). These findings provide critical benchmarks for incorporating digital biomarkers into MS clinical trials and personalized care.

Abstract

Background: Digital health technologies allow for frequent, remote gait monitoring in people with multiple sclerosis (MS). However, to differentiate daily variability from actual disease progression in longitudinal data, established minimal clinically important differences (MCID) are required. Currently, there is limited literature defining these thresholds for digital gait metrics. Objective: To establish MCIDs for digital gait measures reflecting progression in MS. Methods: Digital gait measures were captured via daily, remote, smartphone-based Two-Minute Walk Tests in CONSONANCE (NCT03523858), a phase 3b study of ocrelizumab in progressive MS. Using an anchor-based approach, median changes from baseline at Week 96 on digital gait measures were computed for patients showing clinically meaningful worsening on either Timed 25-Foot Walk, Ambulation Score, Expanded Disability Status Scale, or 12-item Multiple Sclerosis Walking Scale. These changes were subsequently triangulated to derive the MCID estimates. Results: 243 patients with progressive MS (female: n=125 (51%); mean [SD] age: 49.3 [9.3]; mean [SD] EDSS: 4.8 [1.4]) had digital gait data available at baseline and Week 96. Median changes were generally consistent across anchors. Triangulated MCIDs are: Step Velocity = -0.16 m/s, Step Velocity Scaled to Walking Time = -0.18 m/s, Step Duration = 0.06 s, Step Length = -0.07 m, Total Number of Steps = -28, and Total Distance Walked = -24 m. Conclusion: These MCIDs provide a framework for interpreting meaningful gait changes and integrating digital measures into MS outcome evaluation. Beyond facilitating novel clinical trial endpoints to evaluate treatment efficacy, they enable objective, real-world monitoring to advance personalized patient care.

Problem

• Minimal Clinically Important Difference
• gait measures
• multiple sclerosis
• digital health
• disease progression

Innovation

• Minimal Clinically Important Difference
• digital gait measures
• smartphone-based assessment
• multiple sclerosis
• remote monitoring