Association between trabecular bone score, 10-year probability risk for fracture, and vertebral fractures in rheumatoid arthritis.

Objectives: The aim was to assess the association and predictive value of trabecular bone score (TBS), fracture risk assessment tool (FRAX), and TBS-adjusted FRAX with prevalent vertebral fractures (VFs) in patients with rheumatoid arthritis (RA).

Methods: Patients diagnosed with RA were included in this cross-sectional study. Clinical data and laboratory tests were collected on the same day as the dual-energy x-ray absorptiometry (DXA) scan. TBS, bone mineral density (BMD), and vertebral fracture assessment (VFA) were obtained from the DXA scan. We used the FRAX tool to assess the 10-year probability of major osteoporotic fracture (MOF-FRAX) and hip fracture (HF-FRAX) with and without BMD. These parameters were further adjusted for TBS. Patients with prevalent VFs were defined as those with moderate to severe VFs from T4 to L4. VFs presence was used as the binary variable in the logistic regressions and receiving operator characteristics (ROC) curves analysis.

Results: Sixty-nine patients were enrolled, with 55.1 % being postmenopausal. The mean TBS was 1.328 ± 0.104. Osteoporosis according to the WHO criteria was present in 39 patients (56.5 %), and six patients (8.7 %) had VFs with thoracic predominance (66.67 %). Univariate and multivariate logistic regression analyses did not show an association between TBS and vertebral fractures, but FRAX scores indicated such an association. The area under the curve (AUC) with 95 % confidence intervals (CI) for the MOF-FRAX score with BMD, MOF-FRAX score without BMD, TBS-adjusted MOF-FRAX score, and TBS were 0.837 [0.686-0.988], 0.795 [0.629-0.961], 0.778 [0.571-0.984], and 0.515 [0.298-0.731], respectively.

Conclusion: In our RA patients, FRAX scores were associated with vertebral fractures (VFs), while TBS was not. The MOF-FRAX score combined with BMD, showed the best AUC for VFs in this population.