Fatigue in psoriasis: a controlled study.

Abstract

Fatigue is associated with various chronic inflammatory diseases, but few studies have focused on its occurrence in psoriasis. To describe fatigue prevalence and degree among patients with chronic plaque psoriasis vs. age- and sex-matched healthy subjects, and to examine how fatigue is influenced by essential clinical and demographic factors. In 84 patients and 84 healthy subjects, fatigue severity was assessed using three different generic fatigue instruments: the fatigue Visual Analogue Scale (fVAS), the Fatigue Severity Scale (FSS) and the Short Form 36 (SF-36) Vitality scale. Cut-off scores for clinically important fatigue were defined as ≥ 4 for FSS, ≥ 50 for fVAS and ≤ 35 for the SF-36 Vitality scale. Disease activity was evaluated using the Psoriasis Area and Severity Index (PASI), and the impact on quality of life with the Dermatology Life Quality Index (DLQI). Patients and healthy control subjects, respectively, showed median fVAS scores of 51 [interquartile range (IQR) 21-67] and 11 (IQR 3-20); FSS scores of 4 (IQR 2·5-5·3) and 1·6 (IQR 1·1-2·2); and SF-36 Vitality scores of 43 (IQR 25-85) and 73 (IQR 65-85). The rates of clinically important fatigue among patients vs. healthy controls, respectively, were 51% vs. 4% (fVAS); 52% vs. 4% (FSS); and 42% vs. 2% (SF-36 Vitality) (P < 0·001 for all differences). Fatigue was associated with DLQI scores, but not PASI scores, in univariate analysis but not in multivariate analysis. Nearly 50% of patients with psoriasis suffered from substantial fatigue. Fatigue severity was associated with smoking, pain and depression, but not with psoriasis severity.