104. THE CO-OCCURRENCE OF AXIAL SPONDYLOARTHRITIS AND FIBROMYALGIA: RESULTS FROM A NATIONAL REGISTER

Abstract

Background: Some patients with axial spondyloarthritis (axSpA) are recognized clinically to have co-morbid fibromyalgia (FM). However, there are no trials to inform how patients are best managed when axSpA and FM occur together. This study aims to provide data on the frequency of co-occurrence and, among persons with axSpA, to characterize persons with co-morbid FM to inform future trials. Methods: The British Society for Rheumatology Biologics Register for Ankylosing Spondylitis (BSRBR-AS) has recruited patients with axSpA since December 2012, across 82 centres in Great Britain. All patients recruited are naïve to anti-TNF biologic therapy and are either newly starting such therapy (biologic cohort) or not (non-biologic cohort) and are then followed up for the duration of the study. At recruitment and follow-up, patients complete measures of disease activity and impact, including quality of life, sleep disturbance, fatigue and mood. Clinical information and measurements are recorded. Since September 2015, patients have completed 2011FM research criteria and, separately, clinicians have confirmed whether they consider the patients to have FM. Results: 886 patients (69% male) were eligible for the current analysis of whom 157 participants (17.7%) met research criteria for FM. Prevalence of FM did not differ according to whether or not a patient met imaging criteria for axSpA. Patients who met FM research criteria reported worse disease activity [BASDAI: mean difference 3.1 (95% CI 2.7, 3.5)], function [BASFI: 3.1 (2.6, 3.5)] and global scores [BAS-G: 3.3 (2.9, 3.8)]. They reported considerably worse Quality of Life (ASQoL difference 7.5 (95% CI 6.6, 8.3); EQ-5D -0.30 (95% CI -0.34, -0.24)] and were significantly more likely to have moderate/severe levels of anxiety (HADS)-anxiety 54.1% v. 16.1%), depression (HADS-depression 42.7% v. 6.9%) and clinically important fatigue (Chalder Fatigue Scale 79.1% v. 32.7%). Absence from work was primarily reported by those who met FM criteria (17% v. 3%), and FM patients also reported their work was impaired around half the time (52% v. 23%). There was, however, no difference in levels of C-reactive protein, extra-spinal manifestations of axSpA (with the exception of a greater swollen joint count) or in history of biologic therapy between those who met and did not meet FM research criteria. Conclusion: Around 1 in 6 patients with axSpA meet research criteria for FM. Those patients have significantly worse markers of disease activity and impact, both on their physical and psychological health. There are no differences, however, in levels of inflammation or most extra-spinal disease manifestations. Developing management approaches that address the unmet needs of axSpA patients with co-morbid FM should be a current research priority.