TBS correlates with bone density and microstructure at trabecular and cortical bone evaluated by HR-pQCT.

INTRODUCTION: Trabecular bone score (TBS) estimates bone microstructure, which is directly measured by high-resolution peripheral quantitative computed tomography (HRpQCT). We evaluated the correlation between these methods and TBS influence on fracture risk assessed by FRAX.

MATERIALS AND METHODS: We evaluated 129 individuals (82 women, 43 postmenopausal) 20 to 82.3 years without prevalent clinical or non-clinical morphometric vertebral fractures, using DXA (spine and hip), HR-pQCT at distal radius (R) and tibia (T) and TBS which classifies bone microarchitecture as normal (TBS ≥ 1.350), partially degraded (1.200 < TBS < 1.350), or degraded (TBS ≤ 1.200).

RESULTS: Spine and hip BMD and HR-pQCT parameters at cortical bone: area (T), density (R,T) thickness (T) and trabecular bone: density (R,T), number (T) and thickness (R) were significantly better in the 78 individuals with normal TBS (group 1) versus the 51 classified as partially degraded (n = 42) or degraded microarchitecture (n = 9) altogether (group 2). TBS values correlated with age (r = - 0.55), positively with spine and hip BMD and all cortical and trabecular bone density and microstructure parameters evaluated, p < 0.05 all tests. Binary logistic regression defined age (p = 0.008) and cortical thickness (p = 0.018) as main influences on TBS, while ANCOVA demonstrated that HR-pQCT data corrected for age were not different between TBS groups 1 and 2. TBS adjustment increased FRAX risk for major osteoporotic fractures and hip fractures.

CONCLUSION: We describe significant association between TBS and both trabecular and cortical bone parameters measured by HR-pQCT, consistent with TBS influence on fracture risk estimation by FRAX, including hip fractures, where cortical bone predominates.