Factors contributing to falls in people with multiple sclerosis: The exploration of the moderation and mediation effects

The prevalence of multiple sclerosis (MS) has significantly increased in recent decades. People with MS have a high risk of falling; these falls may lead to serious injuries, affecting their quality of life PURPOSE: The aim of this study is to assess the factors affecting falls in people with MS and map out the most significant ones. This study also aims to determine whether fatigue has a moderation effect and balance has a mediation effect on falls in people with MS METHODS: In total, 103 people with MS with a mean age of 32.09 ± 7.17 were enrolled. All subjects were assessed for multiple variables including balance using the Berg Balance Scale (BBS), speed of gait using the Timed Up and Go (TUG) test, fear of falling using the Falls Efficacy Scale-International (FES-I), level of fatigue using the Modified Fatigue Impact Scale (MFIS), and lower limb muscle strength using a handheld digital dynamometer RESULTS: Simple binary logistic regression analysis showed significant results for BBS (OR: 10.88; 95% CI: 4.24-27.96; p < 0.0001), TUG (OR: 1.18; 95% CI: 1.09-1.28; p < 0.0001), FES-I (OR: 1.06; 95% CI: 1.02-1.10; p = 0.001), and MFIS (OR: 1.04; 95% CI: 1.02-1.07; p < 0.0001) as factors affecting falls. According to multivariate analysis, balance (OR: 3.924; 95% CI: 1.307-11.780, p = 0.015), speed of gait (OR: 1.122; 95% CI: 1.023-1.231; p = 0.015), and fatigue (OR: 1.029; 95% CI: 1.002-1.058; p = 0.038) were the strongest predicting factors of falls. Hayes's PROCESS analysis showed that fatigue had a significant moderation effect on the relationship between gait speed and falls (MFIS; β; 0.10; p < 0.0001; 95% CI: 0.07-0.14) and balance had a mediation effect on the relationship between gait speed and falls (BBS; indirect effect; 0.08; 95% CI: 0.02-0.13) CONCLUSIONS: People with MS with impaired balance, slower gait speeds, higher levels of fatigue, and a fear of falling were at a high risk of falling. The relationship between gait speed and falls can be mediated by impaired balance and moderated by the level of fatigue. Our data suggest that targeting balance and fatigue while developing rehabilitation interventions could decrease the incidence of falls among people with MS.