AB0857 The burden of disease in patients with non-radiographic axial spondyloarthritis is not inferior to that of ankylosing spondylitis. the proof study

Background According to the 2009 ASAS classification criteria, a patient with chronic low back pain (CLBP) may be classified as axial spondyloarthritis (ax-SpA), with or without radiographic evidence of sacroiliitis, if at least one other SpA feature is present in the first case and positive HLA-B27 and at least two SpA features in the second one. There is concern about whether the classification ”axial non-radiographic spondyloarthritis” (ax-SpA-nr) includes patients with a mild disease that do not require treatment or special care by rheumatology. Objectives To compare disease burden between patients fulfilling criteria for AS and ax-SpA-nr. Methods Sub-analysis of Spanish patients from the PROOF study, an international prospective observational longitudinal study conducted in rheumatology clinics. All patients who attended rheumatology clinics due to CLBP (≥3 months, start Results 192 patients with CLBP were included, of whom 151 (79%) met criteria of SpA-axe, 56 (43%) of AS and 74 (57%) of ax-SpA-nr (21 patients had X-ray missing or no central reading had been done so far). The table shows the description of patients with AS and ax-SpA-nr and their comparison. Conclusions Patients referred by CLBP to rheumatology clinics meeting ASAS criteria for AS or ax-SpA-nr differ little in terms of impact and disease activity; therefore, non-radiographic forms of ax-SpA require as much attention as classic AS. Acknowledgements The PROOF study was sponsored by AbbVie. AbbVie contributed to the study design, research, and interpretation of data, writing, reviewing, and approving the publication. The authors wish to thank Loreto Carmona (InMusc) for providing medical writing and editing services in the development of this abstract. The financial support for these services was provided by AbbVie. Disclosure of Interest E. de Miguel Mendieta Grant/research support from: Abbvie, S. Munoz Fernandez Grant/research support from: Abbvie, C. Montilla Morales Grant/research support from: Abbvie, J. Ruiz Martin Grant/research support from: Abbvie, D. Reina Sanz Grant/research support from: Abbvie, C. Aguilera Cros Grant/research support from: Abbvie, M. A. Belmonte Serrano Grant/research support from: Abbvie, J. R. Noguera Pons Grant/research support from: Abbvie, C. Barbazan Alvarez Grant/research support from: Abbvie, M. Arranz Employee of: Abbvie, V. Diaz Employee of: Abbvie