L. Gossec ^1,*, S. Paternotte ², M. A. D’Agostino ³, M. Dougados ², B. Fautrel ¹

¹Paris 6 UPMC University, Pitié-Salpétrière hospital, ²Rheumatology B Department, Cochin Hospital, Paris, ³Rheumatology Department, Ambroise Paré hospital, Boulogne-Billancourt, France

Abstract

Background Patient-perceived symptoms such as pain, stiffness, and fatigue are important in spondyloarthritis (SpA); in established SpA, fatigue is frequent. The causes of fatigue in inflammatory rheumatisms such as SpA or rheumatoid arthritis are unclear; fatigue is diversely reported as being related either to patient characteristics, e.g., demographic, psychological and social factors, or to disease characteristics, e.g. disease activity.
Objectives To evaluate the magnitude of fatigue in early SpA (and in the different subtypes of SpA) and to assess if fatigue appears more strongly associated with patient- or with disease-related characteristics.
Methods Patients: Those in DESIR, a national observational cohort of patients with recent (<3 yrs duration) inflammatory back pain suggestive of SpA according to the investigator.
Magnitude of fatigue was assessed by a visual analog scale 0-10 assessment at inclusion and at one year, in the whole population, and according to satisfaction of the ASAS classification criteria, and also to disease subtype (axial versus peripheral versus undifferentiated).
Factors associated with high fatigue (>5/10) at 12 months were assessed by multivariate logistic regression, only for patients satisfying the ASAS criteria. The factors tested for association were patient related characteristics including demographic variables (age, gender, symptom duration) and socio-economic status; disease-related characteristics at 12 months including activity (ASDAS, BASFI, BAS-G, HAQ-AS) and other characteristics (HLA B27, disease subtype, and extra-articular involvement).
Results Of the 708 DESIR patients (mean±SD age 34±9; 327: 46% males), 486 fulfilled the ASAS criteria for SpA (mean age 33±9; 244: 50%, males). Magnitude of fatigue was high at baseline (mean fatigue, 5.7±2.3) and was similar in patients fulfilling the ASAS criteria or not (respectively, mean fatigue 5.5±2.4 and 6.0±2.2). Fatigue levels according to the disease subtype were also similar. Fatigue decreased over the first year of follow-up (mean fatigue at one year, 4.9±2.6).
High fatigue at 12 months was well explained (AUC of the model, 0.86) by the following elements: ASDAS-CRP (odds ratio, 2.5 [1.8-3.3], p<0.0001), BASFI (OR, 1.06 [1.04-1.09], p<0.0001), BAS-G (OR, 1.12 [1.02-1.24], p=0.021) and HAQ-AS (OR, 0.41 [0.18-0.95], p=0.037).
Conclusions Fatigue levels were high in patients with symptoms compatible with early SpA but fatigue did not discriminate between patients with or without the ASAS criteria for SpA. Fatigue levels decreased over the first year of follow-up in DESIR, possibly due to the treatments given. High fatigue at one year was closely related to disease activity rather than to patient-related variables, indicating fatigue seems more strongly related to the disease process in SpA than in rheumatoid arthritis.
Disclosure of Interest: None Declared