AB0823 DUAL ENERGY X-RAY ABSORPTIOMETRY IN PATIENTS WITH SPONDYLOARTHRITIS. CORRELATION WITH DISEASE DURATION, ACTIVITY AND CHANGES IN SACROILIAC JOINTS ON MAGNETIC RESONANCE IMAGING

Abstract

BackgroundBone loss (osteopenia or osteoporosis) and osteoporotic vertebral fractures are well-known complications of spondyloarthritis (SpA), and their prevalence in SpA patients (pts) is higher than in patients with mechanical low back pain [1, 2]. Osteopenia and osteoporosis can develop in both the late and early stages of SpA. The presence of bone marrow edema at the lumbar spine and sacroiliac joints (SIJ) on magnetic resonance imaging (MRI) was more common among pts with low BMD (bone mineral density) than normal BMD [3, 4]. At the same time, the dynamics of osteoporotic and osteosclerotic changes in the spine during the progression of SpA makes the assessment of DEXA results ambiguous.ObjectivesTo determine the presence of osteopenia/osteoporosis in pts with SpA and to establish its correlations with disease duration, disease activity, active changes in SIJ on MRI.Methods40 patients with SpA (55% – male, mean age 39.87±9.79, mean disease duration – 6.75±7.43 years) underwent DEXA. Spondyloarthritis Research Consortium of Canada (SPARCC) MRI SIJ score (0-72) was utilized for evaluation of the active inflammatory lesions in SIJ, Danish MRI scoring method (0-48) – for chronic changes. Disease activity was measured by Bath Ankylosing Spondylitis Disease Activity Index (BASDAI, cm), Ankylosing Spondylitis Disease Activity Score (ASDAS), C-reactive protein (CRP, mg/l), and erythrocyte sedimentation rate (ESR, mm/hr). For correlation, the Spearman correlation coefficient was calculated.ResultsThe mean value of DEXA parameters were: BMD – 0.72±0.15, T-score – -0.16±0.88, Z-score – 0.17±0.89 (forearm); BMD – 0.96±0.17, T-score – -1.13±1.35, Z-score – -0.88±1.31 (spine); BMD – 0.85±0.14, T-score – -0.85±0.93, Z-score – -0.56±0.97 (hip).Mean value (M±σ) of indices and laboratory parameters were: BASDAI – 4.44±1.76, ESR – 30.2±24.1, CRP – 17.9±19.7, ASDAS-CRP – 3.07±1.13, ASDAS-ESR – 3.14±1.14. SPARCC score was 12.3±11.8, Danish score – 15.2±7.77.Osteoporosis was present in 7 (17.5%), osteopenia - in 24 (60%) SpA pts.There was positive correlation between BMD at forearm and Danish MRI score (r=0.331, p=0.02). The CRP level showed negative correlation with BMD at hip (r=-0.322, p=0.02), BMD at spine (r=-0,288, p=0,038) and T-score at spine (r=-0.301, p=0.031). Patient’s age showed negative correlation with BMD at hip (r=-0.268, p=0.05). Disease duration negatively correlated with BMD (r=-0.343, p=0.016) and T-score (r=-0.310, p=0.027) at hip. All correlations were weak. No other correlations were found.ConclusionAmong disease activity parameters, only high CRP was associated with a decrease in BMD for both the back and hip. A decrease in hip BMD was also associated with the patient’s age and disease duration. Regarding MRI indicators, only chronic changes in SIJ, measured by MRI, positively correlated with BMD at forearm only.