Trabecular Bone Score has Limited Ability to Discriminate Fragility Fractures in Postmenopausal Women with Osteopenia: A Danish Case-Control Study

INTRODUCTION: Most fragility fractures occur in women with osteopenia, defined by a BMD T-score between - 1.0 and - 2.5. Although bone mineral density (BMD) is used to estimate fracture risk, bone strength is determined by both bone mass and quality. Degraded trabecular bone score (TBS) has been shown to be independently associated with increased fracture risk. Notably, some individuals with osteopenia have degraded TBS despite only modest reductions in BMD. We aimed to investigate the potential value of TBS in discriminating between postmenopausal women with osteopenia with and without fragility fractures. METHODS: We conducted a retrospective case-control study (1:1) of women with osteopenia at Aarhus University Hospital. Cases had experienced a fragility fracture and were identified through attendance in our Fracture Liaison Service between 01.05.2022-29.04.2024 Controls were referrals for DXA with clinical risk factors. Cases and controls were matched on age (± 5 years). RESULTS: We matched 305 cases with 305 controls. TBS was significantly lower in cases (1.28 IQR(1.20;1.35) vs.1.31 (1.23;1.37), p < 0.01). No differences were found in BMD at any site. Each SD decrease in TBS was associated with a 24% greater odds ratio of a fracture (OR 1.24, 95% CI 1.05;1.48; p < 0.01). Adjusting for weight, height and total hip BMD, the association between TBS and fracture was nonsignificant (p = 0.12). ROC curve analysis demonstrated an AUC of 0.45, TBS failing to discriminate between cases and controls. CONCLUSION: TBS was significantly lower in women with a fragility fracture compared nonfractured controls but showed limited clinically relevant discriminatory performance between women with and without fractures in our Danish cohort.