The Trabecular Bone Score Predicts Spine Fragility Fractures in Postmenopausal Caucasian Women Without Osteoporosis Independently of Bone Mineral Density.

Introduction: The trabecular bone score (TBS) is a gray-level textural metric that can be extracted from the two-dimensional lumbar spine dual-energy X-ray absorptiometry (DXA) image. TBS is related to bone microarchitecture. Several literature data suggest that TBS predicts fracture risk as well as lumbar spine bone mineral density (LS-BMD) measurements in postmenopausal women.

Objective: A retrospective case-control study assessing the ability of the TBS to predict spine fragility fractures (SFF) in postmenopausal women with or without osteoporosis (diagnosed by T-score≤-2.5).

Methods: LS-BMD and the TBS were determined in the L1-L4 vertebrae. Statistical analyses were carried out in the entire group of women (entire-group) (n.699), in women both with osteoporosis (osteoporosis-subgroup) (n.253) and those without osteoporosis (non-osteoporosis-subgroup) (n. 446).

Results: At the unpaired t-test, both the TBS and the LS-BMD (p≤0.001) were lower in women with SFF (n.62) in the entire-group. In the non-osteoporosis subgroup, the TBS (p≤0.009) was lower in women with SFF (n.29). In the osteoporosis subgroup, the LS-BMD (p≤0.003) was lower in women with SFF (n.33). Considering the TBS and LS-BMD separately in a block logistic regression, the TBS was associated with SFF in the entire-group (odds ratio (OR): 1.599, 95% confidence interval (CI): 1.021-2.128) and in the non-osteoporosis-subgroup (OR: 1.725, 95% CI:1.118-2.660) whereas LS-BMD was associated with SFF in the entire-group (OR: 1.611, 95% CI: 1.187-2.187) and in the osteoporosis-subgroup (OR: 2.383, 95% CI: 1.135-5.003). According to forward logistic regression, entering the TBS, LS-BMD and confounders as predictors, the LS-BMD in the entire-group (OR: 1.620, 95% CI: 1.229-2.135) and in the osteoporosis subgroup (OR: 2.344, 95% CI: 1.194-4.600), and the TBS in the non-osteoporosis subgroup (OR: 1.685, 95% CI: 1.131-2.511) were the only predictors of SFFs.

Conclusions: In the entire-group, the TBS predicted SFFs almost as well as LS-BMD, but not independently of it. The TBS, but not LS-BMD, predicted SFFs in the non-osteoporosis subgroup.