High Fatigue Levels Impact Functional Mobility, Quality of Life and Depression in People with Multiple Sclerosis

Background: Fatigue is a commonly presenting symptom in People with Multiple Sclerosis (PwMS). The associations between fatigue and neurological disability, functional mobility, depression and quality of life (QOL) are unclear in MS, therefore demanding further investigation.

Objectives: This study aimed to determine the effect of different levels of fatigue on disability, performance-based and self-reported functional mobility, depression, physical and mental QOL in PwMS.

Methods: Ninety-one individuals [30M/61F; Mean(SD) Age= 54.3(11.9) yrs; diagnosis duration= 13.6(9.8) yrs; EDSS=5.3(1.5); height= 169(10.2) cms; weight= 79(21.5) kgs] with clinically definite MS, no concurrent relapses were included and retrospectively analyzed. Subjects were divided in 2 groups based on a Modified Fatigue Impact Scale-5 (MFIS-5) cut-off score, Group LF (n=34, MFIS-5≤10, representing low levels of fatigue) and Group HF (n=57, MFIS-5>10, representing high levels of fatigue). Functional mobility measures included 8-feet Timed Up-and-Go (TUG), Activities-specific Balance Confidence (ABC) and MS Walking Scale (MSWS-12). Depression was assessed by Beck Depression Inventory-Fast Screen (BDI-FS) and QOL was determined by physical and mental composites of MSQOL-54 questionnaire. Mann Whitney tests for independent samples were used for non-parametric statistical analysis.  

Results: High fatigue levels (MFIS-5>10) were noted in 62.6% of the PwMS. As compared to Group LF, Group HF demonstrated significantly impaired TUG (Mdn secs Group HF= 9.18 vs. Group LF= 7.50; U= 706.00; z= -1.96; p<0.05; r= -0.21), ABC (Mdn % Group HF= 50.62 vs. Group LF= 72.80; U= 658; z= -2.55; p<0.01; r= -0.27), MSWS-12 (Mdn Group HF= 58.33 vs. Group LF= 31.67; U= 336; z= -3.79; p<0.001; r= -0.43), BDI-FS (Mdn Group HF= 3 vs. Group LF= 1; U= 310.5; z= -2.81; p<0.01; r= -0.34), physical QOL (Mdn Group HF= 39.56 vs. Group LF= 59.4; U= 374; z= -4.88; p<0.001; r= -0.51) and mental QOL (Mdn Group HF= 68.29 vs. Group LF= 83.01; U= 490; z= -3.26; p<0.001; r= -0.35). EDSS was similar across both the groups (MdnGroup HF= 5.25 vs. Group LF= 6.0 ; U= 794.00; z= -1.33; p>0.05).

Conclusions: Fatigue is a predominant symptom in PwMS. Individuals with high fatigue levels exhibit significant and clinically meaningful impairments in performance-based as well as self-reported functional mobility, depression, physical and mental QOL . Therefore, effective interventions targeting fatigue may result in improvements in functional performance, depression and QOL in PwMS. Neurological disability was not found to be related to the level of fatigue experienced by PwMS.