Association of Disease Outcomes With Physical Activity in Multiple Sclerosis: A Cross-Sectional Study

Impact and Implications Physical activity levels are reduced in persons with multiple sclerosis (MS) and are explained by MS disease outcomes. This study contributes to the existing literature by examining MS disease outcomes that could comprehensively explain physical activity subgroups in persons with MS. The combinations of walking, symptoms, and cognitive variables contribute to differentiating the subgroups of this health behavior in MS differentially. These preliminary findings indicate that disease outcomes of walking endurance, walking limitations, depression, fatigue, and processing speed should be considered when designing and delivering physical activity behavioral interventions for persons with MS. Rehabilitation psychologists might simultaneously targeting these outcomes for improving physical activity levels in MS. Purpose/Objective Research: This study examined combinations of disease outcomes (i.e., walking, cognition, and symptoms) as correlates of physical activity subgroups (insufficiently active vs. sufficiently active) in persons with multiple sclerosis (MS). Research Method/Design: This study included 213 participants who completed walking and cognitive function tests and self-report measures of symptoms and physical activity. Multivariate analysis of variance and discriminant function analysis identified combinations of MS outcomes associated with physical activity. Results: The sample had a mean age of 49.6 years (SD = 13.2), a 3:1 female:male ratio, and a Patient Determined Disease Steps median (interquartile range) score of 1.0 (3.0). Multivariate analysis of variance demonstrated that MS outcome clusters were significantly associated with physical activity, namely walking (i.e., Six-Minute Walk, Timed Up and Go, and MS Walking Scale), Pillai's trace V = .16, F(3, 180) = 11.43, eta(2) = .16; cognition (i.e., Symbol Digits Modalities Test, California Verbal Learning Test-Second Edition, Brief Visuospatial Memory Test-Revised), Pillai's trace V = .04, F(3, 204) = 2.79, eta(2) = .04; and symptoms (i.e., fatigue, anxiety, depression, and pain), Pillai's trace V = .16, F(4, 199) = 9.30, eta(2) = .16. Discriminant function analysis indicated that a significant discriminant function of walking endurance and walking limitations, depression, fatigue, and processing speed was associated with physical activity subgroups. Conclusion/Implications: The findings identified walking endurance and limitations, processing speed, depression, and fatigue as primary correlates of physical activity differences in persons with MS. These results may inform researchers and health care providers to consider these factors in behavior change interventions and clinical practices for promoting adequate physical activity levels in MS.