Identification of rheumatoid arthritis patients with vertebral fractures using bone mineral density and trabecular bone score

Abstract

The aim of this study was to test bone mineral density (BMD), trabecular bone score (TBS), and their combination, for detection of rheumatoid arthritis (RA) patients with vertebral fractures (VFs). One hundred eighty-five women aged 56.0 ± 13.5 yr, with RA since 15.5 ± 9.9 yr were studied. Lumbar spine, total hip, and femoral neck BMD were assessed by dual-energy X-ray absorptiometry (DXA). TBS was calculated from anteroposterior image of lumbar spine BMD. VFs from T4 to L4 were evaluated using Vertebral Fracture Assessment software on DXA device. The proportions of patients with VF and T-scores ≤-2.5 were only 24.2%, 21.2%, and 33.3% at lumbar spine, total hip, and femoral neck, respectively. T-scores were significantly lower in patients with VF than in patients without VF, the largest difference being observed at femoral neck (p=0.0001). TBS was significantly lower in patients with VF vs without VF (p=0.0001). The areas under the curves were 0.621, 0.704, 0.703, 0.719, and 0.727 for lumbar spine BMD, TBS, lumbar spine BMD+TBS, total hip BMD, and femoral neck BMD, respectively. The threshold of 1.173 for TBS had the best sensitivity (63%) and specificity (74%). TBS measured at the lumbar spine has a better discrimination value than lumbar spine BMD, and similar to femoral neck BMD, for prediction of presence of VF in patients with RA. In RA subjects with osteopenia, the proportion of patients with VF was higher in the lowest tertile of TBS when compared with the highest tertile. In this population, at low risk according to BMD, TBS could help to detect patients with VF.