The Role of Fatigue in the Course of Axial Spondyloarthritis

Objectives: Disease-related fatigue is the most frequently reported symptom by patients with axial Spondyloarthritis (axSpA). The objective of this study was to characterise the patients with axSpA according to the evaluation of disease-related fatigue. Methods: 120 patients were included in the cross-sectional study fulfilling the Assessment of Spondyloarthritis International Society (ASAS) classification criteria for axSpA. Fatigue was evaluated using the first item of the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI) questionnaire. Patients were divided into two groups: with the evaluation of fatigue ≤5 and >5. The following variables were chosen for characteristics: age, duration of the disease, the age of axSpA onset, duration of morning stiffness, pain in spine, Ankylosing Spondylitis Disease Activity Score (ASDAS), functional (BASFI), metrological (BASMI) indices, the evaluation of enthesitis, history of uveitis, and peripheral arthritis. Results: The mean fatigue score was 5.0 (SD 2.59). 44.2% of patients experienced severe fatigue. The mean value of age, duration of morning stiffness, ASDAS, BASFI, BASMI and evaluation of enthesitis, as well as the presence of peripheral arthritis in the group with fatigue level ≤5 were lower than in the second group (p<0.05). There was no difference between groups on duration of the disease, age of axSpA onset, uveitis. Conclusions: Patients with severe fatigue had a higher level of the disease activity, pain, functional disability and spinal mobility impairment. These results suggest that the score of fatigue can be used as the measurement for the expression of systemic inflammation and impairment of mobility independent of the disease duration.