A Prospective Observational Case-Control Study on Bone Mineral Density in Asian-Indians With and Without Femoral Neck Fragility Fractures and Delineation of Fracture Thresholds.

Abstract

Introduction: The present study aims to compare bone mineral density (BMD) between adults with femoral neck (FN) fragility fractures and an equal number of age- and sex-matched healthy controls and delineate sex-specific BMD cut-offs that could predict FN fragility fractures.

Materials and methods: Adult patients with FN fragility fractures admitted at our institution between January 2017 and December 2018 were enrolled. Patients with secondary causes of osteoporosis were excluded. Eligible patients underwent measurement of BMD using dual-energy X-ray absorptiometry. As controls, we selected age- and sex-matched healthy North Indian adults without any history of fractures from the Chandigarh Urban Bone Epidemiological Study (CUBES).

Results: After exclusion, 120 cases (mean age = 67.1 ± 10.1 years) with FN fragility fractures were included (women n = 61). An equal number of age-, sex- and ethnicity-matched healthy controls (n = 120) were selected from CUBES. Controls had significantly higher BMD at both FN and lumbar spine (L1-L4) than cases. Receiver operating characteristic (ROC) analysis showed that in women, FN BMD ≤ 0.680 gm/cm² and L1-L4 BMD ≤ 0.888 gm/cm² predicted fragility fractures with sensitivities of 82.0% and 83.6%, respectively. Likewise, in men, FN BMD ≤ 0.709 gm/cm² and L1-L4 BMD ≤ 0.982 gm/cm² predicted fragility fractures with a sensitivity of 89.8% each. The corresponding specificities were however low in both the sexes.

Conclusions: Adults with FN fragility fractures have lower BMD than age- and sex-matched healthy controls. Although specific BMD thresholds predicting fragility fractures are forthcoming with relatively good sensitivities, they have low specificities thereby possibly limiting their use in routine clinical practice.