Fatigue and psychosocial variables in autoimmune rheumatic disease and chronic fatigue syndrome: A cross-sectional comparison.

OBJECTIVE: Fatigue is common in autoimmune rheumatic diseases (ARD). This study compared symptom-related cognitions, beliefs, behaviours, quality of sleep, lack of acceptance and distress in participants with ARD such as rheumatoid arthritis (RA), seronegative spondyloarthropathy (SpA), and connective tissue disease (CTD), and participants with chronic fatigue syndrome (CFS). METHODS: 303 participants with RA, SpA, CTD and CFS completed questionnaire measures of fatigue, social adjustment, cognitive-behavioural responses, lack of acceptance, distress and quality of sleep. The RA, SpA and CTD groups were first compared with each other. They were then combined into one group and compared with the CFS group. RESULTS: There were no statistically significant differences between the RA, SpA or CTD groups for any of the measures. The CFS group was more fatigued, reported more distress and sleep disturbance and had worse social adjustment than the ARD group after adjustment for age and illness duration. After adjustment for fatigue, age, and illness duration, the CFS group scored more highly on lack of acceptance and avoidance/resting behaviour while the ARD group showed significantly higher levels of catastrophizing, damage beliefs, and symptom focusing than the CFS group. CONCLUSION: Fatigue in rheumatic diseases may be perpetuated by similar underlying transdiagnostic processes. The ARD and CFS groups showed similarities but also key differences in their responses to symptoms. Specific aspects of treatment may need to be tailored towards each group. For example, lack of acceptance and avoidance behaviour may be particularly important in perpetuating fatigue in CFS.