The Fatigue Assessment Scale (FAS) may be a valid and reliable instrument to assess fatigue in patients with systemic lupus erythematosus (SLE), according to results from a study published in Arthritis Research & Therapy.
Researchers conducted a cross-sectional study of 73 patients with active SLE who were assessed for fatigue using the FAS, a novel 10-item self-reported questionnaire. The Short Form 36 (SF-36) was also administered to participants with SLE, in addition to a group of matched control patients with primary Sjogren syndrome. The team evaluated the construct validity, reproducibility, and internal consistency, as well as the convergence, of the tool. Subsequently, these parameters were compared with the vitality subscale of the SF-36.
After analysis, the researchers found that among SLE participants, the instrument showed favorable internal consistency (Cronbach’s alpha, 0.93), test-retest reliability (intraclass correlation coefficient, 0.90), and unidimensionality. In addition, the team reported that the FAS correlated well with the vitality subscale of the SF-36. Researchers also found that the total FAS was highest in active SLE and primary Sjogren syndrome, and higher in non-active SLE compared with healthy control participants.
One key limitation of the analysis was the cross-sectional design of the study.
“This study validates the FAS as a simple and reliable tool to assess fatigue in patients with SLE and shows a close and positive correlation of fatigue with disease activity, independently from corticosteroid use and psychiatric medication,” the researchers wrote.
Horisberger A, Courvoisier D, Ribi C. The Fatigue Assessment Scale as a simple and reliable tool in systemic lupus erythematosus: a cross-sectional study. Arthritis Res Ther. 2019;21(1):80.