In individuals with rheumatoid arthritis (RA) and healthy controls, at enrollment and one year later, we evaluated relationships between diverse psychosocial characteristics and fatigue in multivariate analyses.
Participants with RA and controls completed the Fatigue Severity Scale (FSS) at enrollment and again after one year. All participants also completed measures of depressive symptoms, anxiety, role satisfaction, social support, social stress, disability, physical activity, and sleep quality at enrollment.
A total of 122 individuals with RA and 122 controls of similar age, sex, education, employment, and marital status were enrolled. Those with RA had more fatigue compared to controls (FSS scores 4.2 +/- 1.2 vs 3.4 +/- 1.1; p < 0.0001) (possible range 1-7, higher score = more fatigue). In cross-sectional multivariate regression analysis for the RA group, more fatigue was associated with more anxiety, more disability, less social support, and more social stress (p <or= 0.03 for each variable, R(2) = 0.48). In cross-sectional multivariate regression analysis for controls, more fatigue was associated with more depressive symptoms and more social stress (p <or= 0.003 for each variable, R(2) = 0.31). Repeat FSS scores at one year also were worse for the RA group (n = 91) compared to controls (n = 89) (4.1 +/- 1.3 vs 3.2 +/- 1.0; p < 0.0001). However, changes in scores from enrollment to followup were not markedly different within patients [0.21 for the RA group (p = 0.05) and 0.08 for controls (p = 0.41)]. Enrollment variables that were associated with worse fatigue at followup, based on longitudinal multivariate regression analysis, were less help at home, more anxiety, and more disability for the RA group (p <or= 0.007 for each variable), and more anxiety and less physical activity for controls (p <or= 0.006 for each variable).
Fatigue was relatively stable over time and was common in both the RA group and controls. In addition, fatigue was more closely associated with psychosocial factors in the RA group, and social stress was identified as a relatively unexplored potentially modifiable variable independently related to fatigue in RA.