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AB0879 Fibromyalgia in patients with ankylosing spondylitis: prevalence and relationship with disease activity

Background Spondyloarthritis (SpA) is an inflammatory rheumatic disease, characterised by spinal involvement, peripheral arthritis, or enthesitis with marked pain, stiffness, and fatigue. Fibromyalgia (FM) may be associated with SpA, and shares some common symptoms. Objectives We aimed to estimate the prevalence of FM in SpA and its influence on the assessment of SpA disease activity. Methods This single-centre cross-sectional study included consecutive patients with SpA according to the Assessment of SpondyloArthritis International Society criteria. FM was diagnosed according to the 2010 American College of Rheumatology criteria. All patients underwent clinical evaluation of disease activity using the Bath Ankylosing Spondylitis Disease Activity Index (BASDAI), the Bath Ankylosing Spondylitis Functional Index (BASFI) and the Ankylosing Spondylitis Disease Activity Score (ASDAS) and then compared in patients with and without FM. Results The study included 100 patients with SpA, 67 males and 33 females with a median age of 44.65 years. The prevalence of fibromyalgia was 20%. Patients fulfilling the criteria of FM presented a higher total BASDAI (5.86 (±1.97) vs. 3.15 (±1.99), p<0.01), higher ASDAS-CRP (3.43 (±1.13) vs. 2.41 (±1), p<0.01), higher ASDAS-VS (3.5 (±1.12) vs. 2.53 (±1.02), p<0.01) and poorer function scores (BASFI) (6.76 (±1.97) vs. 3.8 (±2.59), p<0.01). Conclusions FM is a frequent comorbidity in patients with SpA. In patients with SpA-FM, disease activity may be overestimated and this overestimation could lead to inappropriate treatment escalation. References [1] Azevedo VF, Paiva E dos S, Felippe LRH, Moreira RA. Occurrence offibromyalgia in patients with ankylosing spondylitis. Rev Bras Reumatol.2010;50:646–50. [2] Salaffi F, De Angelis R, Carotti M, Gutierrez M, Sarzi-Puttini P, Atzeni F.Fibromyalgia in patients with axial spondyloarthritis: epidemiological profileand effect on measures of disease activity. Rheumatol Int. 2014;34:1103–10. Disclosure of Interest None declared