Article
Similarities and Differences between Non-radiographic and Radiographic Axial Spondyloarthritis in PROOF Cohort
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Authors
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Denis Poddubnyy
- Charité - Universitätsmedizin Berlin, Medizinische Klinik mit Schwerpunkt Gastroenterologie, Infektologie, Rheumatologie, Berlin
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Robert Inman
- University of Toronto, Toronto, Canada
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Joachim Sieper
- Charité - Universitätsmedizin Berlin, Medizinische Klinik mit Schwerpunkt Gastroenterologie, Infektologie, Rheumatologie, Berlin
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Servet Akar
- Izmir Katip Celebi University School of Medicine, Izmir, Türkey
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Santiago Muñoz-Fernández
- Hospital Universitario Infanta Sofía, Universidad Europea, Madrid, Spanien
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Maja Hojnik
- AbbVie, Ljubljana, Slovenien
| Published: | September 4, 2017 |
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Outline
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Background: Previously, some differences between non-radiographic and radiographic axial spondyloarthritis (axSpA) have been reported in national observational studies, mostly from Europe. Herein, we compare the baseline (BL) characteristics of patients (pts) with nr-axSpA and radiographic axSpA (ankylosing spondylitis, AS) from a large multinational cohort of pts with recently diagnosed axSpA.
Methods: PROOF is a prospective observational study evaluating clinical and radiographic outcomes in axSpA pts in rheumatology clinical practice in 29 countries. axSpA pts fulfilling ASAS classification criteria were eligible if diagnosed ≤1 year prior to study enrolment. Investigator‘s confidence with axSpA diagnosis was ascertained on a numeric rating scale (NRS 0-10). At BL, demographic and clinical data as well as radiographs of the sacroiliac joints (SIJ) were collected. Classification as nr-axSpA or AS was based on grading of available radiographs according to modified New York criteria, first by a local reader and then by a central reader (CR). In the case of a disagreement in the classification, a 2nd CR, blinded to the previous assessments, graded the radiograph and the final classification was made based on the decision of 2 out of 3 readers.
Results: 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 axSpA diagnosis was 8.7±1.8. Based on the central assessment of evaluable radiographs, 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, HLA-B27+, and treated with TNF inhibitors (Table 1 [Tab. 1]). Nr-axSpA pts had a significantly higher prevalence of enthesitis, psoriasis and inflammatory bowel disease (IBD). Pt-reported outcomes reflecting burden of disease were mostly comparable between the two subgroups, but BASDAI was significantly higher in the nr-axSpA subgroup (Table1 [Tab. 1]).
Conclusion: There were a few differences between nr-axSpA and AS pts in the multinational 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 SIJ. However, the clinical burden of disease was comparable between the two subgroups of axSpA.
