The currently used ASAS classification criteria for axSpA were developed in 20091 and despite their worldwide acceptance they lack specificity, but since back pain is common greater specificity would be helpful. In this context, ASAS and SPARTAN decided to update the 2009 criteria, based on a data-driven approach through the large international CLASSIC study. Overall, 1,015 patients referred to a rheumatologist with undiagnosed back pain indicative of axSpA were assessed and clinical, biological, and imaging criteria and their combinations were compared to the gold standard: the rheumatologist’s diagnosis for axSpA.
MRI of the sacroiliac joints (SIJ) indicative of axSpA by assessment of both inflammatory and structural lesions had the highest association with the diagnosis of axSpA. HLA-B27, elevated CRP, and several clinical criteria including inflammatory back pain, inflammatory bowel disease, acute anterior uveitis, heel enthesitis, and psoriasis were also included in the revised criteria. The final proposal achieved sensitivity of 79.5% and specificity of 90.4% in the validation dataset.
Presenting the work, Walter Maksymowych said “The ASAS–SPARTAN revised classification criteria for axSpA emphasise the central role of imaging and incorporate a more focused set of clinical variables compared to the 2009 ASAS criteria.”
Another timely update was shared in a poster from Peter Mandl and colleagues, updating the original evidence-based EULAR recommendations on the use of imaging in the diagnosis and clinical management of both axial and peripheral SpA. Twelve key research questions on the role of imaging – formulated in the 2015 recommendations using the PICO method3 – were adopted for the update. Imaging modalities included radiography, ultrasound, magnetic resonance imaging (MRI), computed tomography (CT), positron emission- and single photon emission computed tomography (PET, SPECT), dual-emission x-ray absorptiometry (DXA), and scintigraphy. The task force formulated three new overarching principles. There was also one new recommendation, and updates for nine of the originals.
The main changes include replacing radiography with MRI of the sacroiliac joint – and spine in case of symptoms in that region – as the first imaging modality for diagnosing axSpA. Radiography or preferably low-dose CT were not mentioned in the previous recommendations for diagnostic purposes, but are now suggested as alternative modalities for the sacroiliac joint if MRI is not available or contraindicated. For monitoring axSpA, MRI can be used to track sacroiliac and spinal inflammation and structural damage, while radiography is suitable for long-term monitoring of structural damage in the spine.
For diagnosis of peripheral SpA, ultrasound or MRI remain the methods of choice, and in addition to inflammatory lesions, structural changes should now also be considered. Ultrasound and MRI are also both now recommended for monitoring structural damage in peripheral SpA, along with radiography.
Source
Maksymowych WP, et al. The 2025 Assessment of SpondyloArthritis International Society (ASAS) and Spondyloarthritis Research and Treatment Network (SPARTAN) Revised Classification Criteria for Axial Spondyloarthritis: Development and Validation in the Classification of AxSpA Inception Cohort Study. Presented at EULAR 2026; OP0236. Ann Rheum Dis 2026; DOI: 10.1136/annrheumdis-2026-eular.B.3196.
Mandl P, et al. EULAR recommendations for the use of imaging in the diagnosis and management of spondyloarthritis in clinical practice – 2025 update. Presented at EULAR 2026; POS0682. Ann Rheum Dis 2026; DOI: 10.1136/annrheumdis-2026-eular.B.2205.
References
1. Rudwaleit M, et al. The development of Assessment of SpondyloArthritis international Society classification criteria for axial spondyloarthritis (part II): validation and final selection. Ann Rheum Dis 2009;68(6):777–83. DOI: 10.1136/ard.2009.108233.
2. Maksymowych WP, et al. The Assessments in Spondyloarthritis International Society (ASAS) and Spondyloarthritis Research and Treatment Network (SPARTAN) Revised Classification Criteria for Axial Spondyloarthritis: Development and Validation in the Classification of Axial SpA Inception Cohort Study. Prsented at ACR 2024; Abstract 0854. Arthritis Rheumatol 2024;76(9):0820.
3. Mandl P, et al. European League Against Rheumatism (EULAR). EULAR recommendations for the use of imaging in the diagnosis and management of spondyloarthritis in clinical practice. Ann Rheum Dis 2015;74(7):1327–39. DOI: 10.1136/annrheumdis-2014-206971.
About EULAR
EULAR is the European umbrella organisation representing scientific societies, health professional associations and organisations for people with rheumatic and musculoskeletal diseases (RMDs). EULAR aims to reduce the impact of RMDs on individuals and society, as well as improve RMD treatments, prevention, and rehabilitation. To this end, EULAR fosters excellence in rheumatology education and research, promotes the translation of research advances into daily care, and advocates for the recognition of the needs of those living with RMDs by EU institutions.
Contact
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Notes to Editors