Young Patients With Back Pain And Maximally 1 Spondyloarthritis Feature: Is It Necessary To Test Hla-B27 Or Image The Sacroiliac Joints?

Background Axial SpondyloArthritis (axSpA) is a heterogeneous disease. The likelihood of diagnosis varies depending upon the presence of the specific SpA-features. It is debated whether additional examinations (i.e. HLA-B27 testing and imaging of the sacroiliac joints (SIJ)) should be performed in patients with a low suspicion of axSpA (0-1 present SpA-features) after clinical examination, physical examination, CRP/ESR measurement.Objectives To investigate if HLA-B27 testing and imaging of the SIJ is useful in young patients with back pain and maximally 1 SpA feature.Methods The SPACE cohort includes patients with chronic back pain (CBP; ≥3 months ≤2 years, onset u003c45 years) recruited from 5 participating centres across Europe. All patients underwent full diagnostic work-up: MRI and x-rays SIJ, HLA-B27 testing and assessment of all other SpA-features. Patients were classified according to the ASAS axSpA-criteria and according to the clinical rheumatologist diagnosis.Results In this analysis, 133 patients were included. Of the 38/133 (28.6%) patients without SpA-features; 4/38 (10.5%) were classified according to the ASAS-axSpA criteria after additional investigations ([table][1]). Three of them were also diagnosed as axSpA by the rheumatologist. Four additional patients were diagnosed axSpA but did not fulfil the ASAS axSpA criteria. Of the 95/133 (71.4%) patients with 1 SpA-feature; 22/95 (23.2%) patients fulfilled the ASAS criteria via the imaging arm. SpA features in these patients were: 7 IBP, 5 IBD, 4 positive family history for SpA, 3 good response to NSAIDs, 2 raised CRP/ESR, 1 enthesitis. Seventeen of these 22 patients were also diagnosed as axSpA by the rheumatologist. Six additional patients were diagnosed axSpA but did not fulfil the ASAS axSpA criteria.![Figure][2] Conclusions In patients with CBP and maximally 1 SpA feature after medical history, physical examination and CRP/ESR measurement, subsequent HLA-B27 testing and imaging led to fulfilment of the ASAS axSpA-criteria in 11% and 23%, respectively. In addition axSpA was the clinical diagnosis in almost twenty percent of this group. Therefore, in patients with maximally 1 SpA feature, axSpA cannot be ruled out without additional imaging and/or HLA-B27 testing.Disclosure of Interest None declared [1]: #F1 [2]: pending:yes