Comprehensive evaluation of accelerometer-based physical activity in persons with multiple sclerosis - The influence of disability status and its impact on walking capacity.

Introduction: Multiple sclerosis has a substantial negative impact on physical activity (PA). However, limited knowledge exists on objectively measured PA levels and types across disability status along with its influence on walking capacity.

Objectives: To (1) determine PA levels/types in persons with MS (pwMS) (overall and across disability status) and in healthy controls (HC), and (2) investigate the association between PA levels/types and walking capacity.

Methods: In this study (n = 280 pwMS, n = 118 HC), pwMS were stratified into subgroups based on the Expanded Disability Status Scale (EDSS): no disability (EDSS 0-1.5), mild (EDSS 2-2.5), moderate (EDSS 3-4.5), and severe (EDSS 5-6.5). PA levels/types were assessed by thigh-worn accelerometry and walking capacity by 2-min Walk Test (2MWT), Six Spot Step Test (SSST), and Timed 25-foot Walk Test (T25FWT). Simple and multiple linear regression analyses were used to investigate associations between PA levels/types and walking capacity in pwMS.

Results: PA levels/types and walking capacity differed (p < 0.05) between HC and pwMS, and this was especially pronounced for counts per minute (CPM) (774±297 vs. 518±261), sedentary time (558±59 vs. 588±82 min), moderate-to-vigorous physical activity (MVPA) (47±26 vs. 27±22 min), and walking (94±33 vs. 75±38 min) with differences being accentuated with advanced disability. PA levels/types were associated with walking capacity (p < 0.001, r = 0.04-0.31), which remained after adjusting for age, sex, Body Mass Index (BMI), EDSS, and time since diagnosis (r = 0.42-0.57). Importantly, certain PA levels outcomes (light PA (LPA) and moderate-to-vigorous PA (MVPA)) and PA types outcomes (walking) were independently associated with walking capacity.

Conclusion: The present cross-sectional study observed that PA levels and types were negatively impacted in pwMS compared to HC, especially with advanced disability status. Furthermore, PA levels (LPA and MVPA in particular) and PA types (walking in particular) were associated with walking capacity, independently of age, sex, BMI, and disability status.