[Associated factors of different fatigue dimensions in elderly patients with rheumatoid arthritis]

Objective: To investigate the associated factors of different dimensions of fatigue in elderly patients with rheumatoid arthritis (RA). Methods: A cross-sectional analysis was performed in the elderly outpatients with RA (age ≥ 60 years) in the First Affiliated Hospital of Sun Yat-sen University from January 2018 to June 2019. Fatigue was measured by Multidimensional Fatigue Inventory-20 (MFI-20) and 36-item Short Form Health Survey-Vitality (SF-36-VT). Physical fatigue and mental fatigue were subsequently measured by MFI-20 subscales. Results: A total of 104 patients were included. Male-to-female ratio was 1∶3.3. The average age was (68±6) years. The MFI-20 score and SF-36-VT score were 60±14 and 64±20, respectively. The score of physical fatigue measured by MFI-20 was 14±3, and mental fatigue scored 10±4 (P<0.001). Arthralgia, disease activity, disability, insomnia, depression and anxiety were correlated with fatigue assessed by MFI-20 (correlated coefficient: 0.48-0.62). Multivariable regression analysis showed that arthralgia and depression were associated with physical fatigue (Standardized regression coefficients were 0.44 and 0.38, respectively). Insomnia, depression and anxiety were associated factors of mental fatigue (Standardized regression coefficients were 0.20, 0.32 and 0.24, respectively). Conclusions: Elderly patients with RA experiencehigh level of fatigue, mainly presenting as physical fatigue. Arthralgia and depression mainly affect physical fatigue, and arthralgia is a critical factor. Insomnia, depression and anxiety are associated with mental fatigue.