OPTIMAL ASSESSMENT OF FATIGUE IN RHEUMATOID ARTHRITIS: VISUAL ANALOG SCALE VERSUS FUNCTIONAL ASSESSMENT OF CHRONIC ILLNESS THERAPY – FATIGUE

Abstract

Background:Fatigue is an important outcome for patients with rheumatoid arthritis (RA). As recommended by the European League Against Rheumatism (EULAR)/American College of Rheumatology (ACR) task force in 2008, fatigue should be measured in all RA clinical trials whenever possible. Despite these recommendations, it is largely ignored and rarely assessed in clinical practice.Objectives:The aim of this study was to compare the scales being used to measure fatigue in RA.Methods:We conducted a cross-sectional study including patients with RA (ACR/EULAR 2010). Patients with other acute or chronic diseases that may induce fatigue (such as cancer, infection or depression) were excluded. Demographic and disease-related data were collected. Fatigue was assessed using two scores. The fatigue Visual Analog Scale (VAS) ranging between 0 and 100 cm. Fatigue was considered mild if the fatigue VAS was <20 cm, moderate if 20≤VAS<50 and severe if VAS>50 cm. The Functional Assessment of Chronic Illness Therapy – Fatigue (FACIT-F) which is a short 13-item questionnaire validated in RA. The score FACIT-F ranges between 0 and 52. Fatigue was considered mild if the FACIT-F score was ≥40, moderate if 20≤FACIT-F<40 and severe if 0≤FACIT-F<20. We used Cohen’s kappa (κ) to determine the agreement between fatigue VAS and FACIT-F. The κ result was interpreted as follows: values ≤ 0 as indicating no agreement and 0.01–0.20 as none to slight, 0.21–0.40 as fair, 0.41– 0.60 as moderate, 0.61–0.80 as substantial, and 0.81–1.00 as almost perfect agreement. A p value inferior to 0.05 was considered significant.Results:We included 100 RA patients (84 women and 16 men) with a mean age of 49.5±10 years old [18-65]. The mean disease duration was 87.3 months [1-360]. RF and ACPA were positive in 75% and 72.6% of cases respectively. The mean pain VAS was 49 cm [0-100]. The mean numbers of tender and swollen joints were 5.3 [0-36] and 1 [0-9] respectively. The mean levels of ESR and CRP were 38.1 mm [10-120] and 10.8 mg/l [2-61] respectively. The mean DAS28 ESR was 3.68 [1.90-8.33].The mean fatigue VAS was 49.1 cm [5-100]. Fatigue was mild in 9% of patients, moderate in 31% of patients, and severe in 60% of patients.The mean FACIT-F score was 27.1 [0-51]. Fatigue was mild in 26% of patients, moderate in 57% of patients and severe in 17% of patients.A fair agreement was noted between the two scores (κ=0.303, p<0.001).The fatigue VAS and FACIT-F were both correlated with the following variables: pain VAS (r=0.685, p<0.001 and r=-0.605, p<0.001), ESR (r=0.384, p<0.001 and r=-0.405, p<0.001), and DAS28 ESR (r=0.684, p<0.001 and r=-0.744, p<0.001).Conclusion:The fatigue VAS and FACIT-F are easy, brief and valid measures for monitoring this symptom and its effects on patients with RA. A fair agreement was noted between the two scores.Disclosure of Interests:None declared