Extra-articular manifestations and burden of disease in patients with radiographic and non-radiographic axial spondyloarthritis

Objective: Although the prevalence of peripheral and extra-articular disease in ankylosing spondylitis (AS) has been assessed in many studies, data on non-radiographic axial spondyloarthritis (nr-axSpA) is scanty. The aim of this study was first, to compare radiographic-axSpA/AS (r-axSpA/AS) and nr-axSpA concerning peripheral arthritis and extra-articular manifestations (EAMs), and second, to assess potential differences between patient subgroups with or without EAMs regarding disease burden. Methods: Data was extracted from our single center axSpA database. Patients having at least one of the EAMs (uveitis and/or inflammatory bowel disease (IBD) and/or psoriasis) were compared to those who did not have EAMs. Patients’ clinical data including disease activity, functional and psychological status, physical limitations, quality of life (QoL) and magnetic resonance imaging of sacroiliac joints (SIJ MR) were evaluated. Results: Patients with nr-axSpA (n=193) were younger, had female predominance, better functional and physical status, higher frequency of bone edema in SIJ MR and peripheral arthritis but similar QoL, prevalence of HLA B27 and EAMs compared to r-axSpA/AS (n=352). The prevalence of current or ever uveitis (14.5 vs 15.3%, p=0.791), psoriasis (6.2 vs 5.4%, p=0.689) or IBD (4.1 vs 3.4%, p=0.663) in nr-axSpA and r-axSpA/AS were similar. In both subgroup of patients, EAMs positive and negative patients had similar functional status and QoL, as well as disease activity and laboratory parameters. Conclusion: Patients with nr-axSpA and r-axSpA/AS have similar prevalence of EAMs and clinical burden of disease. Having EAMs does not have a major influence on clinical parameters and patient reported outcome measures in nr-axSpA and r-axSpA/AS.