Association of Continuous Assessment of Step Count by Remote Monitoring With Disability Progression Among Adults With Multiple Sclerosis

Importance Disability measures in multiple sclerosis (MS) fail to capture potentially important variability in walking behavior. More sensitive and ecologically valid outcome measures are needed to advance MS research. Objectives To assess continuous step count activity remotely among individuals with MS for 1 year and determine how average daily step count is associated with other measures of MS disability. Design, Setting, and Participants In a prospective longitudinal observational cohort study, 95 adults with relapsing or progressive MS who were able to walk more than 2 minutes with or without an assistive device were recruited between June 15, 2015, and August 8, 2016, and remotely monitored in their natural environment for 1 year. Patients were excluded if they had a clinical relapse within 30 days or comorbidity contributing to ambulatory impairment. Longitudinal analysis was performed from October 2017 to March 2018. Revised analysis was performed in December 2018. Intervention Activity monitoring of step count using a wrist-worn accelerometer. Main Outcomes and Measures Average daily step count compared with in-clinic assessments and patient-reported outcomes. Results Of the 95 participants recruited (59 women and 36 men; mean [SD] age, 49.6 [13.6] years [range, 22.0-74.0 years]), 35 (37%) had progressive MS, and the median baseline Expanded Disability Status Scale score was 4.0 (range, 0-6.5). At 1 year, 79 participants completed follow-up (83% retention). There was a modest reduction in accelerometer use during the 1 year of the study. A decreasing average daily step count during the study was associated with worsening of clinic-based outcomes (Timed 25-Foot Walk, β = −13.09; P
This longitudinal cohort study assesses how remote monitoring of continuous step count activity for 1 year among individuals with multiple sclerosis is associated with other measures of multiple sclerosis disability.
Key Points Question Is remote monitoring of continuous activity for 1 year among individuals with multiple sclerosis associated with other measures of ambulatory disability? Findings In this longitudinal cohort study, 95 individuals with multiple sclerosis were asked to wear accelerometers for 1 year; at baseline, a low step count was associated with increased risk of clinical worsening at 1 year. Step count reduction during the study was associated with worsening of clinic-based and patient-reported outcomes and occurred even when conventional disability measures remained stable. Meaning Remote step count monitoring might represent a sensitive longitudinal outcome measure with direct implications for multiple sclerosis clinical trials and care.