THE UTILITY OF TBS-ADJUSTED BMD T-SCORE IN THE DISCRIMINATION OF THE MAJOR OSTEOPOROTIC FRACTURES IN THE POSTMENOPAUSAL WOMEN OF THE ROTTERDAM AND THE OSTEOLAUS STUDIES

Abstract

Introduction Lumbar spine (LS) trabecular bone score (TBS) can be used to modify the output from FRAX to enhance fracture prediction. Leslie et al. (ASBMR 2017) proposed an alternative approach for using TBS in clinical practice based upon a risk-equivalent offset adjustment to the bone mineral density (BMD) T-score. The aim of this study is to test whether the TBS-adjusted BMD T-score (BMDTBS T-score) outperforms BMD T-score in the detection of major osteoporotic fractures (MOF). Methods Our study included 3,018 postmenopausal women (age 46-99 y) from the OsteoLaus (N=1,314) and the Rotterdam (N=1,704) Studies. All women had DXA scans (Hologic Discovery or GE-Lunar Prodigy) of LS and hip (TH). In total, 413 prevalent MOF were self-reported. BMDTBS T-score of femoral neck (FN), TH or LS were calculated using the formulas provided by Leslie et al..Contingency 2 × 2 tables were divided according to the WHO osteoporosis definition (BMD T-score ≤-2.5, or BMDTBS T-score≤-2.5) and according to the presence of prevalent MOF. Sensitivity and specificity of BMD T-score and BMDTBS T-score were then calculated. Additionally, a t-test was performed to study whether non-fractured women classified as osteoporotic by the BMDTBS T-score but not by the BMD T-score, had a higher FRAX probability for MOF. Results Women who fractured were older, had lower TBS, BMD T-score and BMDTBS T-score in all three regions. The results of the analysis on sensitivity and specificity are shown in Table 1. In general, the BMDTBS T-score showed a higher sensitivity than BMD T-score in MOF detection, whereas BMD T-score was more specific. Nevertheless, the increase in sensitivity of the BMDTBS T-score was superior to the decrease in specificity. The non- fractured women classified as osteoporotic by BMDTBS T-scorebut not by BMD T-score, had a significantly higher FRAX probability (all p Conclusion This study illustrates how the adjustment of BMD by TBS contributes to MOF discrimination by increasing the sensitivity. As BMD has been shown to have low sensitivity, this need in the field might be filled by the information provided by TBS. This approach considers both bone parameters and postulates itself as a helpful strategy to improve patient care in regions where intervention guidelines are based solely on the BMD T-score.