Establishment Of A Clinical Prediction Model For Lower Extremity Deep Vein Thrombosis Within 24 Hours Of Closed Lower Extremity Fracture Based On Nomogram Model

Objective: Lower extremity closed fracture is a relatively common fracture type.Deep vein thrombosis(DVT)within 24 hours of lower extremity closed fracture can further increase the difficulty of clinical treatment.In this study,the incidence of DVT in patients with lower extremity closed fracture admitted within 24 hours was retrospectively analyzed to improve people’s cognition of DVT,the risk factors of DVT in patients with lower extremity closed fracture were analyzed,and the risk factors of DVT in patients with lower extremity closed fracture within 24 hours were screened.Furthermore,the prediction model of DVT risk line graph in patients with lower extremity closed fracture was constructed to provide a theoretical basis for early identification of high risk patients with DVT.Methods: A total of 255 patients with closed lower limb fractures admitted to our hospital from January 2019 to March 2021 were selected as the research objects.A total of 204patients(80%)were randomly selected as the modeling group according to the ratio of 8:2,and 51 patients(20%)were selected as the test group In the syndrome group,the general clinical data of all patients with closed lower extremity fractures were collected.According to the results of color Doppler ultrasound examination of lower extremity veins at admission,the patients were divided into thrombosis group and non-thrombosis group.Univariate and multivariate Logistic regression were used to analyze the risk factors of DVT in patients with lower extremity closed fracture.R(R3.5.3)was used to establish a nomogram model for predicting DVT in patients with lower extremity closed fracture,and the established nomogram model was verified.Results: Among the 204 patients with lower extremity closed fracture in the model group,39 patients had lower extremity deep vein thrombosis,and 165 patients did not have lower extremity deep vein thrombosis,and the incidence of lower extremity deep vein thrombosis was 19.12%(39/204).Thrombus group and non thrombosis patients’ gender,educational level,local,marital status,smoking history,drinking history,history of tea drinking,hypertension,hyperlipidemia,coronary heart disease,cerebral infarction,arrhythmia,history of tumor,fracture and reset modes,operation time,preoperative waiting time,and the general data,such as the hospital D-dimer of contrast,There was no significant difference between the two groups(P>0.05),but there were significant differences in the proportion of general information such as age,BMI,diabetes,multiple fractures,ASA grade,hematocrit and the degree of hemoglobin HGB decline between the two groups(P<0.05).Multivariate Logistic regression analysis showed that age(≥ 45 years old)(OR =4.917,95%CI: 1.981-12.201)and BMI(≥ 25kg/m2)(OR =4.048,95%CI: 1.676-9.778),diabetes mellitus(yes)(OR =2.500,95%CI: 1.075-5.812),multiple fractures(yes)(OR =3.104,95%CI: 1.284-7.503),preoperative ASA grade(grade 3)(OR =3.165,95%CI: 1.411-7.097),hematocrit(≦36%)(OR =2.4341,95%CI: 1.041-5.689)and HGB decline(>30g/L)(OR =6.397,95%CI: 1.866-21.928)were independent risk factors for deep vein thrombosis within 24 hours in patients with lower extremity closed fracture(P<0.05).The C-index of the model group was 0.819(95%CI: 0.787-0.851),and that of the validation group was 0.842(95%CI:0.804-0.880).The calibration curve shows that the actual value and the predicted value of the model group and the validation group have a good fitting degree,as shown in Figure 2and Figure 3.The AUC of the model group and the validation group were 0.798 and 0.826,respectively.Conclusion: The rate of lower extremity deep vein thrombosis within 24 hours of lower extremity closed fracture was 19.12%.Age ≥ 45 years old,BMI ≥ 25kg/m2,diabetes mellitus,multiple fractures,preoperative ASA3 grade,hematocrit ≤ 36%,and HGB decline>30g/L are independent risk factors for lower extremity deep vein thrombosis within 24 hours in patients with lower extremity closed fracture.During clinical treatment,medical staff can establish a nomogram risk pre-examination model based on the above 7 risk factors,which will help medical staff to clarify the risk probability of patients with high risk of lower extremity DVT.