SAT0395 Similarities and differences between non-radiographic and radiographic axial spondyloarthritis in proof cohort
Authors: D Poddubnyy, RD Inman, J Sieper, S Akar, S Muñoz-Fernández, M Hojnik
Journal: Annals of the Rheumatic Diseases (2017)

<h3>Background</h3> Previously, some differences between non-radiographic and radiographic axial spondyloarthritis (axSpA) – such as a higher prevalence of females and lower level of acute phase reactants in non-radiographic axSpA (nr-axSpA) – have been reported in national observational studies, mostly from Europe. <h3>Objectives</h3> To compare demographic and clinical characteristics of patients (pts) with nr-axSpA and radiographic axSpA (ankylosing spondylitis, AS) in a large multinational cohort of pts with recently diagnosed axSpA. <h3>Methods</h3> PROOF is a prospective observational study evaluating clinical and radiographic outcomes in axSpA pts in rheumatology clinical practice in 29 countries. Pts with axSpA fulfilling ASAS classification criteria were eligible if diagnosed ≤1 year prior to study enrolment. Investigator9s confidence with the diagnosis of axSpA was ascertained on a numeric rating scale (NRS 0–10) at enrolment and end of follow-up. At baseline, demographic and clinical data related to the diagnosis, disease activity, quality of life and work productivity, as well as conventional radiographs of the sacroiliac joints were collected. Classification as nr-axSpA or AS was based on the results of the assessment of sacroiliac radiographs. Available radiographs were assessed first by a local reader and then by a central reader according to the grading system of the modified New York criteria. In the case of a disagreement in the classification (nr- axSpA or AS), the radiograph was evaluated by the 2nd central reader, who was blinded to the previous assessments and the final classification was made based on the decision of 2 out of 3 readers. <h3>Results</h3> Of the 2126 pts enrolled in PROOF, 1281 (60.3%) pts were classified as AS and 845 (39.7%) as nr-axSpA according to investigators. The confidence with the diagnosis of axSpA was 8.7±1.8. The final classification according to the central assessment of sacroiliac radiographs was confirmed in1583 pts included in this analysis. A total of 987 pts (62.3%) were classified as AS and 596 (37.7%) as nr-axSpA. AS pts expectedly had longer symptom duration, more frequently had elevated and higher CRP and were more often male and treated with TNF inhibitors (Table). In addition, HLA-B27 positivity was more frequent among AS pts, while pts with nr-axSpA had a significantly higher prevalence of enthesitis, psoriasis, and inflammatory bowel disease (IBD). The prevalence of other SpA features was comparable between the two subgroups of axSpA. Mostly, pt-reported outcomes reflecting burden of disease were comparable between the two subgroups, but BASDAI was significantly higher in the nr-axSpA subgroup (Table). <h3>Conclusions</h3> There were a few differences between nr-axSpA and AS pts in the PROOF cohort. The clinical constellation of female sex, low CRP, enthesitis, psoriasis, and IBD in nr-axSpA pts appears to reflect a phenotype less prone to structural damage in the sacroiliac joints. However, the clinical burden of disease was comparable between the two subgroups of axSpA. <h3>Acknowledgements</h3> AbbVie funded the PROOF study, contributed to its design and participated in data collection, analysis and interpretation of the data, and in writing, review, and approval of the publication. Medical writing support was provided by Deepa Venkitaramani, PhD, of AbbVie. <h3>Disclosure of Interest</h3> D. Poddubnyy Grant/research support from: AbbVie, Janssen, MSD, Novartis, Pfizer, Consultant for: AbbVie, BMS, Boehringer, MSD, Novartis, Pfizer, and UCB, Speakers bureau: AbbVie, BMS, Janssen, MSD, Novartis, Pfizer, Roche, and UCB, R. Inman Grant/research support from: AbbVie, Amgen, and Janssen, Consultant for: AbbVie, Amgen, Janssen, Lilly, Novartis, and Pfizer, J. Sieper Grant/research support from: AbbVie, Merck, and Pfizer, Consultant for: AbbVie, Janssen, Lilly, Merck, Novartis, Pfizer, and UCB, Speakers bureau: AbbVie, Janssen, Merck, Novartis, Pfizer, Roche, and UCB, S. Akar Grant/research support from: AbbVie, BMS, MSD, Novartis, Pfizer, Roche, and UCB, Consultant for: AbbVie, BMS, MSD, Novartis, Pfizer, Roche, and UCB, Speakers bureau: AbbVie, BMS, MSD, Novartis, Pfizer, Roche, and UCB, S. Muñoz-Fernández Grant/research support from: Abbvie, BMS, Janssen, MSD, Novartis, Pfizer, Roche, and UCB, Consultant for: Abbvie, BMS, Janssen, MSD, Novartis, Pfizer, Roche, and UCB, Speakers bureau: Abbvie, BMS, Janssen, MSD, Novartis, Pfizer, Roche, and UCB, M. Hojnik Shareholder of: AbbVie, Employee of: AbbVie