EXPERIENCE USING DIFFERENT CRITERIA OF FIBROMYALGIA IN PATIENTS WITH ANKYLOSING SPONDYLITIS: 1990 AMERICAN COLLEGE OF RHEUMATOLOGY CLASSIFICATION CRITERIA VS. NEW

Background: Fibromyalgia (FM) is a very frequent condition in patients with diseases associated with pain syndrome, such as rheumatoid arthritis (RA), ankylosing spondylitis (AS) and other chronic rheumatic diseases. FM, RA and AS has different clinical characteristics, but can share symptoms such as pain, fatigue and sleep disturbance that leads to delay in appropriation correct diagnosis [1]. For today well known many different criteria for FM: 1990 American College of Rheumatology (ACR) classification criteria, modified 2010 ACR diagnostic criteria, 2016 Fibromyalgia Diagnostic Criteria and new AAPT Diagnostic Criteria for Fibromyalgia. According to the literature, prevalence FM in AS patients can reach from 12.6 to 28.5%, but prevalence estimates should be interpreted with care as no data that the criteria for FM have been validated for use in patients with AS and other chronic inflammatory arthritis [1, 2]. The lack of appropriate information needs further investigation for better identification FM. Objectives: The aim of our study was to compare the presence of FM by 1990 ACR classification criteria, modified 2010 ACR diagnostic criteria, 2016 Fibromyalgia Diagnostic Criteria and new criteria FM 2019 - AAPT Diagnostic Criteria for Fibromyalgia in AS patients. Methods: One hundred and thirteen AS patients (19 women and 94 men) with mean age (M ± SD) 42.3±10.94 years were enrolled in the study. Diagnosis AS was established according to modified New York criteria. For FM detection were used 1990 ACR classification criteria, modified 2010 ACR diagnostic criteria, 2016 Fibromyalgia Diagnostic Criteria and AAPT Diagnostic Criteria for Fibromyalgia. All patients were asked to complete self-reported disease-related questionnaires for patients with AS. Results: According 1990 ACR criteria, FM met in 26 patients (23%). 38.1% patients were positively screened for FM due to modified 2010 ACR diagnostic criteria, and in 31.9% patients according 2016 Fibromyalgia Diagnostic Criteria, and in 41.6% patients due to AAPT Diagnostic Criteria for Fibromyalgia. All new criteria correlated with 1990 ACR classification criteria with p Conclusion: Our study results confirmed very high prevalence FM in patients with AS.The most sensitive tool for detection FM in patients with AS were the modified 2010 ACR diagnostic criteria with sensitivity of 96% and specificity of 79%.The similar percentages of FM due to different classification criteria might be a good sign in context of the validity of these criteria for AS patient. References: [1]Zhao, S. S., Duffield, S. J., & Goodson, N. J. (2019). The prevalence and impact of comorbid fibromyalgia in inflammatory arthritis. Best Practice & Research Clinical Rheumatology, 1014-23. [2]Salaffi, F., De Angelis, R., Carotti, M., Gutierrez, M., Sarzi-Puttini, P., & Atzeni, F. (2014). Fibromyalgia in patients with axial spondyloarthritis: epidemiological profile and effect on measures of disease activity. Rheumatology international, 34(8), 1103-1110. Disclosure of Interests: : None declared