Updated trabecular bone score accounting for the soft tissue thickness (TBSTT) demonstrated significantly improved bone microstructure with denosumab in the FREEDOM TBS post hoc analysis.

Summary: TBS algorithm has been updated to account for regional soft tissue noise. In postmenopausal women with osteoporosis, denosumab improved tissue thickness–adjusted TBS vs placebo independently of bone mineral density over 3 years, with the magnitude of changes from baseline or placebo numerically greater than body mass index–adjusted TBS. Introduction: To evaluate the effect of denosumab on bone microarchitecture assessed by trabecular bone score (TBS) in the FREEDOM study using the updated algorithm that accounts for regional soft tissue thickness (TBS_TT) in dual-energy X-ray absorptiometry (DXA) images and to compare percent changes from baseline and placebo with classical body mass index (BMI)–adjusted TBS (TBS_BMI). Methods: Postmenopausal women with lumbar spine or total hip bone mineral density (BMD) T score < − 2.5 and ≥ − 4.0 received placebo or denosumab 60 mg subcutaneously every 6 months. TBS_BMI and TBS_TT were assessed on lumbar spine DXA scans at baseline and months 1, 12, 24, and 36 in a subset of 279 women (129 placebo, 150 denosumab) who completed the 3-year FREEDOM DXA substudy and rolled over to open-label extension study. Results: Baseline characteristics were similar between groups. TBS_TT in the denosumab group showed numerically greater changes from both baseline and placebo than TBS_BMI at months 12, 24, and 36. Denosumab led to progressive increases in BMD (1.2, 5.6, 8.1, and 10.5%) and TBS_TT (0.4, 2.3, 2.6, and 3.3%) from baseline to months 1, 12, 24, and 36, respectively. Both TBS changes were significant vs baseline and placebo from months 12 to 36 (p < 0.0001). As expected, BMD and TBS_TT were poorly correlated both at baseline and for changes during treatment. Conclusion: In postmenopausal women with osteoporosis, denosumab significantly improved bone microstructure assessed by TBS_TT over 3 years. TBS_TT seemed more responsive to denosumab treatment than TBS_BMI and was independent of BMD. [ABSTRACT FROM AUTHOR]