E05 Is subchondral bone marrow edema predictive of bone mineral density loss in juvenile idiopathic arthritis?

Abstract

Introduction Inflammation plays a crucial role in impaired bone metabolism [1]. Subchondral bone marrow oedema (BME) in Magnetic Resonance Imaging (MRI) was associated to bone mineral density (BMD) loss in adult spondyloarthritis [1]. BME was less studied in juvenile idiopathic arthritis (JIA). Objectives We aimed to study the link between MRI BME and BMD in JIA patients. Methods We conducted a retrospective study of 44 patients with JIA who fulfilled the International League of Associations for Rheumatology (ILAR) 2001 criteria. For each patient we collected the following data: age, age at the onset of JIA, JIA subtype, disease duration, C-reactive protein (CRP) and Erythrocyte sedimentation rate (ERS) levels, BMD assessed using bone densitometry and MRI. Disease activity was assessed using the JADAS score. Statistical analysis was performed using SPSS software. Results We included 28 boys and 16 girls. The mean age was 13.65 ± 4.62 years. The mean age at the onset of the disease 9.57 ± 3.97 years. The mean disease duration was 4.34 ± 3.09 years. There was enthesitis-related arthritis in 61% of the cases (n = 27), oligoarticular JIA in 14% of the cases (n = 6), polyarticular JIA in 11% of the cases (n = 5), and psoriatic arthritis in 7% of the cases (n = 3). JIA was undifferentiated in 7% of the cases (n = 3). The mean CRP and ESR were 14.42 ± 19.67 mg/l and 26.56 ± 20.87 mm, respectively. The mean JADAS was 6.6 ± 4.7. Bone densitometry was performed in 17 patients. The mean BMD and the mean Z-score were 0.961 ± 0.128 g/cm2 and -0.4 ± 1.16 standard deviation, respectively. Magnetic resonance imaging (MRI) showed BME in 52% of the patients (n = 23). Bone marrow oedema was present in the sacroiliac joints in 43% of the cases (n = 19), in the coxofemoral joints in 27% of the cases (n = 12), and in the spine in 9% of the cases (n = 4). The presence of BME was associated with a higher ESR (32.71 ± 25.71 vs 18.94 ± 10.72 mm, P = 0.032), higher JADAS (8.01 ± 5.36 vs 4.75 ± 3.29, P = 0.023), and a lower Z-score (-1.3 ± 0.77 vs 0.4 ± 0.8 standard deviation, P = 0.001). Conclusion Our study showed that MRI BME was associated with high disease activity and BMD loss in JIA patients. This result is consistent with those of Akgöl et al. [2]. Bone marrow oedema seems to predict BMD loss in JIA and should lead to optimizing the treatment. References [1]. Wang D, Hou Z, Gong Y, Chen S, Lin L, Xiao Z. Bone oedema on magnetic resonance imaging is highly associated with low bone mineral density in patients with ankylosing spondylitis. PLoS One 2017;12:e0189569. [2]. Akgöl G, Kamanlı A, Ozgocmen S. Evidence for inflammation-induced bone loss in non-radiographic axial spondyloarthritis. Rheumatology 2014;53:497–501.