THU0708-HPR CORRELATIONS BETWEEN FATIGUE AND PATIENT REPORTED OUTCOME IN PEOPLE WITH INFLAMATORY ARTHRITIS 
Authors: Bente Appel Esbensen, Sandra Elkjær Stallknecht, Maria Madsen, Lise Hagelund, Trine Pilgaard
Journal: Annals of the Rheumatic Diseases (2019)

<h3>Background</h3> Fatigue is one of the most common symptoms of people with inflammatory arthritis (IA) and often rated as high as or higher than pain. However, it remains unexplored how fatigue is associated with patient related outcomes (PRO) such as work impairment, quality of life, sleep, depression, physical functioning and pain. <h3>Objectives</h3> To explore fatigue and to analyze possible correlations between fatigue and PROs in people with rheumatoid arthritis (RA), psoriatic arthritis (PsA) and axial spondyloarthritis (axSpA). <h3>Methods</h3> A cross-sectional study. People ≥18 years with a confirmed diagnosis of RA, PsA or axSpA were consecutively recruited for the study over a 6-month period via routine visits to outpatient rheumatology clinics in two hospitals departments. Trained study nurses collected information on informed consent, diagnosis, medical treatment and disease activity status. Fatigue was evaluated by a self-completed questionnaire using the FACIT-Fatigue sub-scale. The questionnaire also included the following PRO scales: Work Productivity and Activity Impairment scale (WPAI), EuroQol (EQ-5D), Medical Outcomes Study Sleep Scale (MOS), Major Depression Inventory (MDI), and Health Assessment Questionnaire (HAQ) on quality of life and pain. Data was analyzed in SAS. Correlations were assessed by a) Pearson correlation coefficients and b) raw and adjusted linear regressions. <h3>Results</h3> In total 633 persons were invited and 487 (77%) (mean age=53.5, SD 14.5) were included (62% women). The mean fatigue score (range 0-52; lower = more fatigued) was 34.3 (SD 11.1) and there was no statistically significant difference between mean fatigue in the three diagnostic groups (p=0.08). Altogether 61% expressed that they were suffering from fatigue (i.e. had a FACIT-Fatigue sub-scale ≤39). Women generally had a lower overall fatigue score (mean=33.3, SD 11.1) than men (mean=36.0, SD 11.0). Fatigue did not differ between age groups (p=0.33). Those who had changed medical treatment within 0-12 months (21.1%) suffered more from fatigue than those with unchanged treatment (mean=30.1, SD 11.7 vs. mean=35.4, SD 10.7, p&lt;0.0001). The average disease activity as indicated by DAS28, BASDAI and BASFI showed low disease activity in the cohort. Current medical treatment (csDMARDs and/or bDMARDs or none) was not associated with severity of fatigue (p=0.85). Fatigue correlated with all PROs (Pearson correlation coefficients, all p-values &lt;0.0001) (Table 1). Increased work impairment, sleep problems, depression, and pain were all associated with increased fatigue, whereas decreased quality of life and physical functioning were associated with increased fatigue (raw and adjusted linear regressions). The associations did not change significantly after additional adjustment for socioeconomic factors. Analyses stratified on type of disease did not differ significantly from the primary non-stratified analysis. <h3>Conclusion</h3> Despite the study cohort represents a stable group with low disease activity, fatigue was a frequently expressed symptom across diagnoses. There was a significant correlation between fatigue and the other PROs why fatigue cannot be seen as a single problem, but rather a symptom that broadly affects people living with inflammatory arthritis. <h3>Disclosure of Interests</h3> Bente Appel Esbensen Speakers bureau: For Pfizer, Sandra Elkjær Stallknecht Consultant for: Paid by Pfizer to work on this and other studies, Maria Madsen Consultant for: Paid by Pfizer to work on this and other studies, Lise Hagelund Shareholder of: Pfizer, Employee of: Pfizer, Trine Pilgaard Shareholder of: Pfizer, Employee of: Pfizer