Mobility trajectories in multiple sclerosis: A comparative study of timed 25-foot walk and a patient-reported outcome measure.

BACKGROUND

Loss of mobility is common in persons with multiple sclerosis (PwMS), but little is known about this impairment from the patient's perspective.

OBJECTIVE

The aim is to model longitudinal variation in a mobility patient-reported outcome (PRO) and compare trajectories to those observed for Timed 25-Foot Walk (T25FW) in a retrospective cohort.

METHODS

Latent-class growth analysis was applied to 47,508 measures of Performance Scales© Mobility PRO (PS-Mobility) over ~4 years for 8524 PwMS. For 7347 PwMS, there were 41,988 T25FW measures during this period. Repeated measures correlation and concordance of trajectory assignment were evaluated.

RESULTS

At the group level, PS-Mobility and T25FW linearly worsened and repeated-measures correlation was moderate. Eight latent classes with varying shapes that worsened described PS-Mobility variation, compared to six latent classes for T25FW that differed by intercept. The agreement between PS-Mobility and T25FW cluster assignment was modest. A higher proportion of individuals who were Black/African American, older, Medicaid beneficiaries, living in deprived neighborhoods, had longer disease duration, had progressive disease, and ever smokers were assigned to more impaired clusters.

DISCUSSION: Cross-sectionally, PS-Mobility and T25FW were highly correlated, but longitudinally correlation was modest to moderate, underscoring the importance of considering both objective and subjective perspectives in evaluating mobility changes in PwMS.