Trabecular bone score as an assessment tool to identify the risk of vertebral fractures in SAPHO syndrome

Summary

This is the first study to report that TBS seems not only unaffected by bone artifacts, but also is superior to BMD in the discrimination of vertebral fractures in SAPHO patients, which highlights the importance of adding TBS measurement to DXA images in routine clinical evaluation.

Purpose

To investigate the impact of bone artifacts on trabecular bone score (TBS) and lumbar spine (LS) bone mineral density (BMD) measured by dual-energy X-ray absorptiometry (DXA) and analyze the clinical utility of TBS evaluation for vertebral fracture (VF) risk assessment in SAPHO patients compared with BMD assessment.

Methods

Seventy SAPHO patients (mean age 50.1 (10.7) years, 81% women) and an equal number of age- and sex-matched controls were enrolled. TBS and BMD were assessed using DXA. Bone artifacts and VF of the spine were evaluated using whole-spine CT. Univariate logistic regression analysis was performed to identify factors associated with VF. Odds ratios (ORs) per standard deviation decrease in TBS and BMDs were estimated from logistic regression models with adjustment for age.

Results

In patients with bone artifacts, TBS, but not LS BMD, was lower than matched controls, and in those without bone artifacts, both BMDs and TBS were lower than controls. After adjustment, LS BMD was significantly lower in the SAPHO group than in controls. TBS and LS BMD (OR [95% confidence interval], 12.0 [3.6, 40.4] and 4.7 [2.0, 10.9]) showed statistically significant ORs but the others did not. For evaluating VF in SAPHO patients, TBS showed the greatest AUC in the ROC curve, with a value of 0.920 compared with 0.777, 0.690, and 0.652 for LS, FN, and TH BMD, respectively.

Conclusion

TBS seems not to be influenced by bone artifacts in opposition to LS BMD and has a better discriminatory value than BMD for VF in SAPHO patients.