THU0392 Bone Mineral Density Changes in Patients with Early Axial Spondyloarthritis
Authors: E. Gubar, T. Dubinina, A. Dyomina, A. Godzenko, O. Rumyantseva, A. Smirnov, S. Glukhova, M. Urumova, S. Erdes, E. Nasonov
Journal: Annals of the Rheumatic Diseases (2016)

<h3>Background</h3> Bone loss in patients (pts) with early axial spondyloarthritis is insufficiently studied. <h3>Objectives</h3> To assess 1-year bone mineral density (BMD) changes at the femoral neck (FN) and lumbar spine (LS) in pts with early axial spondyloarthritis (axSpA). <h3>Methods</h3> 47 pts (20 men and 27 women) with axSpA and &lt;5 years duration of inflammatory back pain (ASAS 2009 criteria) of the Russian CORSAR cohort were observed. Pts included had baseline and 1-year-visit BMD measurements. Pts matched the ASAS criteria and were observed according to ASAS guidelines. At baseline, the median age was 27.0 (24.0–31.0) years, disease duration 22.0 (10.0–34.0) months. 90% of pts were HLA-B27 positive. 46% of pts alongside inflammatory back pain also had peripheral arthritis. Median BASDAI was 3.5 (2.1–5.2), ASDASCRP 2.3 (1.4–3.2), ESR 9.0 (5.0–24.5) mm/h, CRP 3.9 (1.0–19.7) mg/L. Femoral neck (FN) and lumbar spine (LS) (L2–4) BMD were measured in all pts using dual-energy x-ray absorptiometry (DXA). Low BMD was defined as Z score ≤-2 SD (at least in one investigated site). MRI of sacroiliac joints (SIJs), LS and hip joints (HJs) (in case of hip joint involvement) were performed using Signa Ovation 0.35 T scanner (matrix 288x192). <h3>Results</h3> In all 47 pts, baseline median Z-score was -0.6 (-1.3 – 0.2) SD for the FN and -0.7 (-1.8 – 0.3) SD for the LS. Z-score for the FN was significantly lower in women: -1.0 (-1.5 – -0.3) SD and 0.0 (-0.75 – 0.4) SD, respectively, p=0.0065. At baseline examination low BMD at least in one of the sites was evidenced in 8 (17%) pts (4 men and 4 women). While all 8 pts had low LS BMD, 3 of them had also low FN BMD. At baseline examination of the 47 pts association between lumbar spine MRI-spondylitis and low BMD was revealed. MRI-spondylitis was evidenced in 8 (17%) pts: 3 (62.5%) of them had low FN and/or LS BMD, while 5 (62.5%) pts of this group had normal BMD values. In contrast, within the group of pts without the LS MRI inflammation (n=39) nobody had low BMD (p=0.0006). Initially, there was found a relationship between high ASDAS activity and low BMD: 11.5% of pts with high ASDASCRP values had low BMD. In contrast, within the group of pts with low or moderate ASDASCRP values nobody had low BMD (p=0.054). Among the 8 pts with low baseline BMD, 1-year BMD normalized in 3 pts (all women and all initially had low LS BMD). In one patient (male) with normal baseline BMD values low LS BMD at the 1-year visit was observed. Therefore, at 1-year visit fewer pts had low BMD than at baseline examination (n=8, 17% vs n=6, 12.8%, respectively). In males the lowering of LS BMD at 1-year visit was evidenced with much higher confidence than in females (5 among 20 pts, 25%, vs 1 among 27 pts, 3.8%, respectively; p=0.043). Neither at baseline examination nor at 1-year visit any correlation was detected between low BMD and disease duration, high disease activity according to BASDAI, raised CRP or ESR levels, the presence of MRI-sacroiliitis or MRI-coxitis. <h3>Conclusions</h3> In the Russian cohort of axSpA pts there was found an association between active MRI-spondylitis of the LS and BMD reduction in LS and/or FN. The findings corroborate the hypothesis that low BMD in pts with early axSpA is a result of inflammation. Males more often than females had lowered LS BMD after 1 year of observation. <h3>Disclosure of Interest</h3> None declared