SEVERE FATIGUE IN PATIENTS WITH SYSTEMIC LUPUS ERYTHEMATOSUS: A STUDY ON THE PSYCHOMETRIC PROPERTIES OF THE SEVERITY FATIGUE SCALE

The main purpose of this study was the adaptation of the Fatigue Severity Scale (Krupp et al., 1989), which was designed to assess the perception of fatigue levels in patients with Systemic Lupus Erythematosus (SLE). Using a sample of 104 patients with SLE, the results showed that the Fatigue Severity Scale had a fidelity coefficient of .96, which indicates a high internal consistency of the items, like the original version (.88). The factor analysis showed the items, in the adapted version, to be organized in one factor only, as it happens in the original version. Thus, the Fatigue Severity Scale has good psychometric qualities that allow its use as an assessment tool in the evaluation the perception of fatigue in the Portuguese population of patients with Systemic Lupus Erythematosus. In terms of construct validity results showed, in patients with SLE, higher perceived fatigue to be associated with low quality of life in every domain (physical, psychological, social relationships and environment) and more depressive and anxiety symptoms.