Assessment of the Concomitance of Fibromyalgia in Patients with Axial Spondyloarthritis and Rheumatoid Arthritis

BACKGROUND/AIMS: Fibromyalgia (FM) is a chronic pain condition in which patients experience diffuse musculoskeletal discomfort accompanied by marked fatigue, non-restorative sleep patterns, and cognitive complaints. Individuals with FM exhibit elevated inflammatory cytokines. The aim was to investigate the prevalence of FM in patients with rheumatoid arthritis (RA) and spondyloarthritis (SpA) and to evaluate the effects of biologic and targeted synthetic disease-modifying antirheumatic drugs (b/tsDMARDs) on FM. MATERIALS AND METHODS: Patients were enrolled in the study, including spondyloarthritis and RA patients. Disease activity in RA patients was assessed using the Disease Activity Score-28 scores. For SpA patients, the Bath Ankylosing Spondylitis Disease Activity Index and the Bath Ankylosing Spondylitis Metrology Index were used to evaluate disease activity and structural damage. Patients were evaluated for FM according to the 1990 American College of Rheumatology classification criteria. The Fibromyalgia Impact Questionnaire was administered for FM severity. RESULTS: There was no significant difference in the prevalence of FM between the RA and SpA groups (P = .942). The prevalence of FM was significantly higher among patients not receiving b/tsDMARDs compared to those who were (P = .033). In the SpA subgroup, no significant difference in FM prevalence was observed between patients using and not using b/ tsDMARDs (P = .314). However, in the RA subgroup, FM prevalence was significantly higher among patients not receiving b/tsDMARDs (P = .030). CONCLUSION: The findings suggest that the use of b/tsDMARDs appears to be associated with a reduced prevalence of FM among patients with RA. It is believed that this study provides a window for future studies. Cite this article as: Caglayan M, Oktayoglu P, Celik Y, et al. Assessment of the concomitance of fibromyalgia in patients with axial spondyloarthritis and rheumatoid arthritis. ArchRheumatol. 2026;41(1):72-80.