胸腰椎骨折内固定术后合并下肢DVT风险预测列线图模型的建立与验证

Establishment and validation of a Nomogram model for risk prediction of lower extremity DVT after internal fixation of thoracolumbar fractures

目的:探讨胸腰椎骨折内固定术后合并下肢深静脉血栓形成(DVT)的危险因素,并据此建立风险预测列线图模型。方法:回顾性分析2019年5月-2022年5月因胸腰椎骨折于医院接受内固定术的225例病人的临床资料,并根据术后是否合并下肢DVT将病人分为合并组(35例)和未合并组(190例)。采用多因素Logistic回归分析法分析胸腰椎骨折内固定术后合并下肢DVT的危险因素,并建立风险预测列线图模型。绘制受试者工作特征曲线(ROC)以评估列线图模型的预测效能,并绘制校准曲线,采用Bootstrap自抽样法内部验证预测列线图模型的区分度。结果:合并组年龄≥60岁、美国脊柱损伤协会(ASIA)分级A级、术中失血量≥1000 mL、输血、术后卧床时间≥4 d的病人占比及术后D-二聚体水平均高于未合并组(P<0.05);多因素Logistic回归分析结果显示,年龄≥60岁、ASIA分级A级、术中失血量≥1000 mL、输血、术后D-二聚体水平高、术后卧床时间≥4 d均是胸腰椎骨折内固定术后合并下肢DVT的危险因素(P<0.05);将上述危险因素作为预测指标,构建胸腰椎骨折内固定术后合并下肢DVT的风险预测列线图模型;ROC曲线分析结果显示,列线图预测胸腰椎骨折内固定术后合并下肢DVT的曲线下面积(AUC)为0.797[95%CI(0.739,0.848)],灵敏度为74.29%,特异度为86.84%;采用Bootstrap自抽样法内部验证一致性指数为0.793,提示区分度良好;校准曲线与标准曲线贴合较好。结论:年龄≥60岁、ASIA分级A级、术中失血量≥1000 mL、输血、术后D-二聚体水平高、术后卧床时间≥4 d均是胸腰椎骨折内固定术后合并下肢DVT的危险因素,据此构建的列线图模型有助于临床筛选高风险病人以预防病人术后下肢DVT发生。

Objective:To explore the risk factors of lower extremity deep vein thrombosis(DVT)after internal fixation of thoracolumbar fractures,and establish a risk prediction Nomogram model.Methods:The clinical data of 225 patients who received internal fixation in hospital due to thoracolumbar fractures from May 2019 to May 2022 were retrospectively analyzed,and the patients were divided into the combined group(35 cases)and the non-combined group(190 cases)according to whether they were combined with lower extremity DVT after surgery.Multivariate Logistic regression analysis was used to analyze the risk factors of lower extremity DVT after internal fixation of thoracolumbar fractures,and the risk prediction Nomogram model was established.Receiver operating characteristic curve(ROC)was plotted to evaluate the prediction efficiency of the Nomogram model,and calibration curve was plotted to internally verify the differentiation of the predictive Nomogram model using Bootstrap self-sampling method.Results:The proportions of patients aged≥60 years old,ASIA grade A,intraoperative blood loss≥1000 mL,blood transfusion,postoperative bed time≥4 d and postoperative D-dimer level in the combined group were higher than those in the non-combined group(P<0.05).Multivariate Logistic regression analysis showed that age≥60 years old,ASIA grade A,intraoperative blood loss≥1000 mL,blood transfusion,high level of postoperative D-dimer,postoperative bed time≥4 d were all risk factors for lower extremity DVT after internal fixation of thoracolumbar fractures(P<0.05).The above risk factors were taken as predictive indicators,the risk prediction Nomogram model of lower extremity DVT after internal fixation of thoracolumbar fractures was constructed.ROC curve analysis results showed that the area under the curve(AUC)of lower extremity DVT after internal fixation of thoracolumbar fractures was 0.797[95%CI(0.739,0.848)],the sensitivity was 74.29%,and the specificity was 86.84%.The internal verification consistency index of Bootstrap self-sampling method was 0.793,indicating good differentiation.The calibration curve fitted the standard curve well.Conclusions:Age≥60 years old,ASIA grade A,intraoperative blood loss≥1000 mL,blood transfusion,high level of postoperative D-dimer,and postoperative bed time≥4 d are all risk factors for lower extremity DVT after internal fixation of thoracolumbar fractures.The Nomogram model constructed based on this is helpful for clinical screening of high-risk patients to prevent the occurrence of lower extremity DVT after surgery.