Objective: To explore whether low aerobic capacity and physical activity are associated with fatigue, when controlling for age, gender, pain and depressive symptoms in persons with rheumatoid arthritis.
Methods: In 60 individuals fatigue (Multidimensional Assessment of Fatigue scale; MAF), disease activity (Disease Activity Score-28; DAS 28), pain, physical and psychological status (Arthritis Impact Measurement Scales 2; AIMS 2), depression (Hospital Anxiety and Depression Scale; HADS), aerobic capacity and physical activity (Short Questionnaire to Assess Health-enhancing physical activity; SQUASH) were measured. Regression was performed to study the variance of fatigue explained by aerobic capacity and physical activity.
Results: Mean (standard deviation (SD)) age of participants was 51.8 (SD 10.4) years and 73.3% were women. Duration of disease was 10.2 (SD 0-41) years and mean disease activity score was 3.4 (SD 1.4). Mean Global Fatigue Index was 20.3 (SD 10.5). Physical function was 1.6 (SD 1.1) and psychological status 3.1 (SD 0-8) on the AIMS2. Pain score was 4.1 (SD 2.0) and median depression score was 3.2 (range 0-15). Total amount of physical activity was 176.9 (10.6-1,492.3) METhours/week and VO2max was 27.8 (SD 3.8) ml/kg/min. Backward multiple regression showed a statistically significant relationship with depressive symptoms only (t = 5.4, p < 0.001), which explained 33% of variance of fatigue in patients with RA.
Conclusion: Depression, but not aerobic capacity or physical activity, contributed to fatigue. However, no relationship was found between aerobic capacity and fatigue.