Department of Epidemiology and Biostatistics, School of Public Health, Jilin University, Changchun, Jilin, China.
Department of Community Health Sciences, University of Manitoba, Winnipeg, MB, Canada.
Osteoporos Int. 2018 Jan;29(1):191-200. doi: 10.1007/s00198-017-4232-8. Epub 2017 Oct 6.
Fracture risk indices (FRIs) generated from DXA-based finite element analysis were associated with hip fracture independent of FRAX score computed with femoral neck bone mineral density (BMD). Prospective studies are warranted to determine whether FRIs represent an improvement over BMD for predicting incident hip fractures.
The study aims to examine the association between prior hip fracture and FRIs derived from automated finite element analysis (FEA) of DXA hip scans. Femoral neck, intertrochanteric, and subtrochanteric FRIs were calculated as the von Mises stress induced by a sideways fall divided by the bone yield stress over the specified region of interest (ROI).
Using the Manitoba Bone Mineral Density Database, we selected women age ≥ 65 years with femoral neck T-scores below - 1 and no osteoporosis treatment. From this population, we identified 324 older women with hip fracture before DXA testing and a random sample of 658 non-fracture controls. FRIs were derived from the anonymized DXA scans. Logistic regression models were used to estimate odds ratios (ORs) and 95% confidence intervals (95% CIs) for the associations between FRIs (per SD increase) and hip fracture.
After adjusting for FRAX score (hip fracture with BMD), femoral neck FRI (OR 1.36, 95% CI 1.13, 1.64), intertrochanteric FRI (OR 1.81, 95% CI 1.44, 2.27), and subtrochanteric FRI (OR 2.09, 95% CI 1.68, 2.60) were associated with hip fracture. Intertrochanteric and subtrochanteric FRIs gave significantly higher c-statistics (all P ≤ 0.05) than femoral neck BMD. Subgroup analyses showed that all FRIs were more strongly associated with hip fracture in women who were younger and had higher body mass index (BMI) or non-osteoporotic BMD (all P < 0.1).
FRIs derived from DXA-based FEA were independently associated with prior hip fracture, suggesting that they could potentially improve hip fracture risk assessment.
研究既往髋部骨折与基于双能 X 线吸收法（DXA）自动有限元分析（FEA）得出的骨折风险指数（FRI）之间的关系。计算股骨颈、转子间和转子下 FRI 的方法为，将侧向跌倒引起的 von Mises 应力除以特定感兴趣区域（ROI）的骨屈服应力。
我们利用马尼托巴省骨密度数据库，选择 T 评分低于-1 且未接受骨质疏松治疗的年龄≥65 岁的女性。在该人群中，我们确定了 324 名在 DXA 检测前发生髋部骨折的老年女性和 658 名非骨折对照者的随机样本。从匿名 DXA 扫描中得出 FRI。使用逻辑回归模型来估计 FRI（每增加一个标准差）与髋部骨折之间的比值比（OR）和 95%置信区间（95%CI）。
在校正了基于 BMD 的 FRAX 评分（髋部骨折）后，股骨颈 FRI（OR 1.36，95%CI 1.13，1.64）、转子间 FRI（OR 1.81，95%CI 1.44，2.27）和转子下 FRI（OR 2.09，95%CI 1.68，2.60）与髋部骨折相关。转子间和转子下 FRI 的曲线下面积（c-statistic）显著高于股骨颈 BMD（均 P≤0.05）。亚组分析显示，所有 FRI 在年龄较小、BMI 较高或非骨质疏松性 BMD 较高的女性中与髋部骨折的相关性更强（均 P＜0.1）。
基于 DXA 的 FEA 得出的 FRI 与既往髋部骨折独立相关，提示其可能有助于改善髋部骨折风险评估。
