Objectives: 

Use a large database design and multivariable analyses to assess the associations between body mass index (BMI) and femur fracture patterns after controlling for other risk factors.

Design: 

Retrospective cohort study.

Setting: 

National insurance claims database of patient records from 2010 to 2018.

Patients/Participants: 

Patients with femur fracture diagnoses were identified. Patients with multiple fractures within 1 week (polytrauma patients), patients without a BMI diagnosis code within 6 months of fracture, and patients with multiple BMI diagnosis codes (implying a substantial change in weight) were excluded.

Intervention: 

N/A.

Main Outcome Measurements: 

Patients were divided into groups based on fracture location: proximal (OTA/AO 31), shaft (OTA/AO 32), or distal (OTA/AO 33). The distribution of femur fractures was compared across BMI categories.

Results: 

A total of 57,042 patients with femur fracture were identified: 45,586 proximal fractures, 4216 shaft fractures, and 7240 distal fractures. Patients with BMI <29.9 have increased odds (P < 0.0001) of proximal fracture and decreased odds (P < 0.0001) of shaft or distal fractures. Patients with BMI >30.0 have decreased odds (P < 0.0001) of proximal fracture and increased odds (P < 0.0001) of distal fractures.

Conclusions: 

Increasing BMI is associated with a decreased proportion of proximal femur fractures and a corresponding increase in the proportion of shaft and distal fractures. Regression analyses determined that age, sex, osteoporosis, diabetes, and tobacco use are not the cause of this trend.

Level of Evidence: 

Prognostic Level III. See Instructions for Authors for a complete description of levels of evidence.

中文翻译：

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体重指数对股骨骨折位置的影响：回顾性数据库研究

目标： 

在控制其他风险因素后，使用大型数据库设计和多变量分析来评估体重指数 (BMI) 与股骨骨折模式之间的关联。

设计： 

回顾性队列研究。

环境： 

2010 年至 2018 年患者记录的国家保险理赔数据库。

患者/参与者： 

确定了诊断为股骨骨折的患者。排除 1 周内多次骨折的患者（多发伤患者）、骨折后 6 个月内无 BMI 诊断代码的患者以及具有多个 BMI 诊断代码（暗示体重发生实质性变化）的患者。

干涉： 

不适用。

主要结果测量： 

根据骨折位置将患者分为几组：近端 (OTA/AO 31)、轴 (OTA/AO 32) 或远端 (OTA/AO 33)。比较不同 BMI 类别的股骨骨折分布。

结果： 

总共确定了 57,042 例股骨骨折患者：45,586 例近端骨折、4216 例股骨干骨折和 7240 例远端骨折。BMI <29.9 的患者发生近端骨折的几率增加( P < 0.0001)，而发生轴或远端骨折的几率降低 ( P < 0.0001)。BMI >30.0 的患者发生近端骨折的几率降低 ( P < 0.0001)，而远端骨折的几率增加 ( P < 0.0001)。

结论： 

BMI 的增加与股骨近端骨折比例的降低以及轴和远端骨折比例的相应增加有关。回归分析确定年龄、性别、骨质疏松症、糖尿病和吸烟不是造成这一趋势的原因。

证据等级： 

预后等级 III。有关证据等级的完整描述，请参阅作者须知。