Fatigue in Patients With Multiple System Atrophy: A Prospective Cohort Study

Background and objectives: Nonmotor symptoms are common in patients with multiple system atrophy (MSA), but there is limited knowledge regarding fatigue in MSA. This study aimed to investigate the frequency and evolution of fatigue and the factors related to fatigue and its progression in patients with MSA at an early stage.

Methods: Patients with probable MSA were comprehensively evaluated at both baseline and the 1-year follow-up, including their motor and nonmotor symptoms. Fatigue and anxiety were assessed using the Fatigue Severity Scale (FSS) and Hamilton Anxiety Rating Scale (HARS), respectively. Orthostatic hypotension (OH) was defined as a decrease in the systolic or diastolic blood pressure by at least 30 and 15 mm Hg, respectively. The binary logistic regression model and linear regression model were used to analyze the factors related to fatigue and its progression, respectively.

Results: This study enrolled 146 patients with MSA. The frequency of fatigue was 60.3%, 55.1%, and 64.9% in MSA, MSA with predominant parkinsonism (MSA-P), and MSA with predominant cerebellar ataxia (MSA-C), respectively. The frequency of fatigue and the FSS score in patients with MSA increased from baseline to the 1-year follow-up (p < 0.05). Young age (odds ratio [OR] 0.939, 95% confidence interval [CI] 0.894-0.987), OH (OR 2.806, 95% CI 1.253-6.286), and high HARS score (OR 1.014, 95% CI 1.035-1.177) were associated with fatigue in MSA. OH was associated with fatigue in MSA-P (OR 3.391, 95% CI 1.066-10.788), while high HARS score was associated with fatigue in MSA-C (OR 1.159, 95% CI 1.043-1.287). In addition, only low FSS scores at baseline were associated with the annual progression rate of FSS scores in MSA, MSA-P, and MSA-C (p < 0.05). Neurofilament light chain, α-synuclein, glial fibrillary acidic protein, brain-derived neurotrophic factor, and triggering receptor expressed on myeloid cell-2 were not significantly associated with fatigue and its progression in MSA.

Discussion: Fatigue was prevalent in early-stage MSA, and it increased and remained persistent over time. This study demonstrated that OH and anxiety were associated with fatigue in patients with MSA.