Objectives To study the association between disease activity (BASDAI/ASDAS-CRP), MRI inflammation of sacroiliac joints (SIJs), lumbar spine (LS) and hip joints (HJs) and bone mineral density (BMD) in early axial spondyloarthritis (axSpA) patients.
Methods 73 patients (33 men and 40 women) with early axSpa (according to ASAS criteria) were studied: disease duration – 19.9±14.4 months. Age –28.3±6.4 years, BASDAI – 4.1±1.9; ASDAS-CRP – 2.7±1.3. BMD was measured using dual energy x-ray absorptiometry (DXA) of femoral neck (FN) and LS (L2-4). BMD was evaluated according to Z-score. MRI of SIJs, LS and HJs (in case of hip joint involvement) was also performed using a scanner Signa Ovation 0.35 T (matrix 288x192). Inflammatory lesions (IL) on MRI (STIR) were evaluated by an independent reader. Cluster analysis was used for interpreting the results.
Results Cluster analysis allowed to group two sets of related indicators. The first set contained the values of activity indices (BASDAI, ASDAS-CRP), as well as the BASFI functional index; the second group – the MRI-IL of SIJs, LS and HJs and the BMD results. Cluster analysis revealed correlation between the two groups (euclidean distance – 20). This indicates an association between the SpA activity indices (BASDAI, ASDAS-CRP) and the values of BMD in LS and FN, as well as inflammatory MRI changes in SIJs, LS and HJs (Fig. 1). Note the low correlation between the inflammation index and ESR and CRP.
Conclusions Early axSpA patients have an association between the MRI inflammation of SIJs, LS and HJs and the BMD reduction in the nearby bone-joint system, their combination with BASDAI and ASDAS activity, and the lack of correlation with acute phase reactants (ESR, CRP).
Disclosure of Interest : None declared