Factors associated with fatigue in patients with systemic lupus erythematosus

Objective-To examine the relation between fatigue, disease activity, damage, and quality of life measures in patients with systemic lupus erythematosus (SLE). Methods-Consecutive patients attending the University of Toronto Lupus Clinic were studied. Disease activity was assessed using the SLEDAI and SLAM-R and damage using the SLICC/ACR Damage index. Fatigue was measured by the Fatigue Severity Score (FSS) and health status by the SF-36 questionnaire. In all cases a tender point count was also performed. Results-81 patients were studied. Their mean (SD) age and disease duration were 43 (12.5) years and 12.7 (8.0) years respectively. The FSS did not correlate with the SLEDAI nor with the SLAM-R. There was no correlation with the SLICC damage index. Fatigue severity correlated with the tender point count (SCC r = 0.46, p < 0.001), and negatively with all domains of the SF36 (r values -0.50 to -0.82). Disease activity and damage accounted for only 4.8% and 4% respectively of the variance in fatigue severity reported by patients. Conclusion-In an outpatient population of SLE patients, fatigue severity correlates with poor health status and a higher tender point count. In patients with SLE, factors associated with quality of life and fibromyalgia seem to have a greater influence on the severity of reported fatigue than does the level of current disease activity.