Discrimination of vertebral fragility fracture with lumbar spine bone mineral density measured by quantitative computed tomography

Abstract

Background/Objective: This study is a case–control study to explore risk and protective factors, including clinical data and bone mineral density (BMD), affecting vertebral body fragility fracture in elderly men and postmenopausal women. In addition, we investigate the effectiveness of lumbar spine BMD by quantitative computed tomography (QCT) in discriminating vertebral fragility fracture. Methods: In this case–control study, 52 males and 198 females with vertebral fragility fracture were compared with sex- and age-matched healthy controls to analyse the risk factors that may affect vertebral fragility fracture. The L1–L3 vertebral BMDs were measured by QCT. The difference in risk factors between fracture cases and controls were analysed using student t test and Mann–Whitney U test. The correlation between BMD, age, height and weight were analysed using univariate analysis. Multiple logistic regression analysis was used to study statistically significant indexes. The receiver operating characteristic curve was used to calculate the cut-off values for positive and negative predictive values of BMD for vertebral fracture discrimination. Results: In males, body weight and BMD were significantly different between the fracture group and the control group, whereas BMD was only weakly correlated with age (r = −0.234). In females, only BMD was significantly different between the fracture and control groups. BMD was weakly correlated with height (r = 0.133) and weight (r = 0.120) and was moderately correlated with age (r = −0.387). There was no correlation between BMD and the remaining variables in this study. In both men and women, the BMD (p = 0.000) was the independent protective factor against vertebral fracture. The cut-off values of vertebral BMD for fractures were 64.16 mg/cm3 for males and 55.58 mg/cm3 for females. QCT-measured BMD has a high positive predictive value and negative predictive value for discriminating vertebral fragility fracture across a range of BMD values. Conclusion: This study suggests that BMD is closely related to vertebral fragility fracture and that QCT is an effective technique to accurately discriminate vertebral fragility fracture. The translational potential of this article: The spine BMD measured by QCT is closely related to fracture, which may allow clinicians to more accurately discriminate which individuals are likely to experience vertebral fragility fracture. Keywords: Bone mineral density, Quantitative computed tomography, Vertebral fragility fracture