Association between thoracolumbar kyphosis and fracture risk assessment tool in Korean postmenopausal women: A retrospective study

Thoracolumbar kyphosis (TLK) has been suggested as a potential risk factor for vertebral fractures in postmenopausal women; however, its association with bone mineral density (BMD), trabecular bone score (TBS), and fracture risk assessment tools, such as the Fracture Risk Assessment Tool (FRAX), remain undefined. In this study, we investigated the association between the TLK level and fracture risk in postmenopausal women. We retrospectively analyzed the associations between the thoracolumbar Cobb (TLCobb) angle, baseline compression fractures, BMD, TBS, and volumetric BMD measured using dual-energy X-ray absorptiometry (DXA) and central quantitative computed tomography (cQCT). The study included 251 postmenopausal women (median age, 61 years; interquartile range, 56–69 years) who visited our hospital for health checkups between March 2020 and December 2021. Fracture risk was assessed using FRAX and TBS-adjusted FRAX. Baseline radiography revealed patients with compression fractures (n = 64, 25.498%), in whom the TLCobb angle was significantly higher. The TLCobb angle demonstrated a significant negative correlation with TBS. Baseline compression fractures and higher TLCobb angles were significant predictors of future fragility compression fractures, with a TLCobb angle > 9.4° established as the threshold value. DXA and FRAX had limitations in predicting future progressive or new-onset compression fractures. In conclusion, TLK was found to be associated with densitometric results, particularly TBS, and has predictive value for future compression fracture risk. Baseline compression fractures with higher TLCobb angles are potential predictors of fracture risk in postmenopausal women.