BackgroundSpondyloarthritis (SpA) is a chronic inflammatory disease that predominantly affects the sacroiliac joints and the spine. Patients with SpA have an increased risk of osteoporosis and fracture resulting from a combination of inflammation and immobility. The non-radiographic form for SpA (nr-axSpA) has the same predictors factors of bone fragility however the real fracture risk is unknown in this phenotype.ObjectivesThis study aims to investigate BMD and the Fracture Risk Assessment

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... (FRAX) in patients with nr-axSpA.MethodsWe conducted a retrospective study including 40 patients with nr-axSpA, according to the ASAS criteria. For the enrolled patient, we collected the clinical and biological data. We calculated the disease activity using the Bath Ankylosing Spondylitis disease activity (BASDAI) and the Ankylosing Spondylitis Disease Activity Score (ASDAS). Functional impairment was assessed by the Ankylosing Spondylitis Functional Index (BASFI). We measured the bone mineral density using the dual-energy X-ray absorptiometry (DXA) in the anteroposterior lumbar, lateral spine, and hip neck. The ten-year probability of major osteoporotic fracture was calculated using the Tunisian version of Fracture Risk Assessment Tool (FRAX).ResultsTwenty-seven women (67.5%) and thirteen men (32.5%) were enrolled. The mean age was 41.5 years (±11.2), and the mean disease duration was 3,1 years (±2.7). The mean BASDAI and ASDAS CRP was 4.7 ± 2.2 and 3.27 ± 1.29, respectively. The mean BASFI was 3.6 ± 2.5. According to World Health Organization (WHO) criteria, 45% of patients displayed osteopenia and 30% osteoporosis. The mean major osteoporotic fracture (MOF) score was 0,09 ± 0,25 [0-1,3]. The MOF was significantly associated with BMD (p=0.000). The variables associated with MOF were a high physician's global assessment score, a high BASFI, and female gender, but without significant relation. However, no correlation was found between the MOF and the disease duration, the presence of peripheral arthritis or enthesitis, and the ASDAS.ConclusionIn nr-axSpA, patients with low BMD had a higher calculated 10-year fracture risk. FRAX score is related to functional impairment and gender. Disease activity does not affect the probability of fracture.Disclosure of InterestsNone declared