Research And Prediction Of Risk Factors And Recurrence Of Pulmonary Embolism In Children And Young Patients With Nephrotic Syndrome

Objective:1.To investigate risk factors of the occurrence and recurrence of pulmonary embolism in children and young adults with nephrotic syndrome.2.To establish a prediction model for the occurrence and recurrence of pulmonary embolism in children and young patients with nephrotic syndrome.Materials and Methods:1.This study retrospectively analyzed children and young adults who were diagnosed with nephrotic syndrome and were younger than 25 years old in the affiliated hospital from January 2010 to October 2018.The presence of pulmonary embolism was determined by CTPA examination.According to CTPA results,patients were divided into pulmonary embolism group and non-pulmonary embolism group.The incidence of nephrotic syndrome in children and young adults was studied in different age groups,sex and pathological types of nephrotic syndrome.Univariate analysis was performed on the basic clinical data of the patients,related biochemical examination,and pathological types of nephrotic syndrome,then logistic regression analysis was used to screen out independent risk factors and establish the model.Receiver operating characteristic（ROC）curve was used to evaluate the performance of the model and the corresponding area under curve（AUC）was calculated.P value less than 0.05 is considered statistically significant.2.Children and young adults（younger than 25 years old）with nephrotic syndrome diagnosed with primary pulmonary embolism by CTPA examination in affiliated hospitals from January 2010 to October 2018 were retrospectively analyzed.Patients were divided into recurrent pulmonary embolism group and non-recurrent pulmonary embolism group by screening there were more than 2 CTPA follow-up examination results.Univariate analysis was performed on the basic clinical data,related biochemical examination and imaging data of the patients,then logistic regression analysis was used to screen out the independent risk factors.Receiver operating characteristic curve（ROC）was used to evaluate the predictive performance and some quantitative parameters to predict the threshold for the recurrence of pulmonary embolism was determined.The corresponding sensitivity,specificity and area under curve（AUC）were calculated.P value less than 0.05 is considered statistically significant.Results:1.A total of 444 patients（310 male and 134 female,mean age 19 ±3 years,ranging in age from 6 to 25 years）were enrolled.The incidence of pulmonary embolism in children and young adults with nephrotic syndrome was 24.8%（110/444,18.2% female）.The risk of pulmonary embolism increased with age,men,prior history of thromboembolism and smoking by comparing the basic clinical data of the pulmonary embolism group and the non-pulmonary embolism group.On laboratory tests,children and young adults with nephrotic syndrome are more likely to have a increasing incidence of pulmonary embolism with elevated levels of proteinuria（>3.5g/d）,D-dimer（>0.5mg/L）,and decreased serum albumin levels（<30g/d）.In terms of renal pathological types,the incidence of pulmonary embolism in patients with membranous nephropathy was significantly higher than other pathological types of nephropathy.In univariate and multivariate analyses,membranous nephropathy and the level of proteinuria were found to be independent risk factors for the development of pulmonary embolism in children and young adults with nephrotic syndrome（P<0.05）.And three predictive models were established based on risk factors,including clinical and biochemical predictive indicators（model 1）,adjust for the level of proteinuria on the basis of model 1（model 2）and adjust for the pathological type of membranous nephropathy on the basis of model 2（model 3）,the AUC values were 0.578,0.657 and 0.709,respectively.It is found that adding the level of proteinuria and pathological types of membranous nephropathy can effectively improve the predictive ability of the model（model 1 vs model 2,P = 0.0336;model 1 vs model 3,P=0.0268;model 2 vs model 3,P=0.2947）.2.A total of 48 children and young adults with nephrotic syndrome with follow-up data were included in this study（median follow-up time was 3 months）,of which 9patients developed recurrent pulmonary embolism events,with a recurrence rate of 18.7%.Compliance with anticoagulant therapy,length of follow-up time,and elevated D-dimer levels at discharge were associated with recurrent pulmonary embolism in children and young adults with nephrotic syndrome compared with non-recurrent patients（P<0.05）.Through univariate and multivariate analysis,it was found that compliance with anticoagulant therapy,length of follow-up time and elevated D-dimer levels at discharge were independent risk factors affecting the recurrence of PE.ROC curve analysis showed that the AUC values were 0.654,0.759 and 0.929,respectively.For the follow-up time,the cutoff value for diagnosis of recurrence was 115 days,with a sensitivity of 88.9% and a specificity of 87.2%.There were no significant differences in imaging quantitative parameters（including the type of pulmonary embolism,CT obstruction index and indicators of right ventricular function）at the time of initial diagnosis of PE（P>0.05）,but these imaging quantitative parameters showed significant difference between the two groups during the follow-up period（P<0.05）.Conclusion:1.The incidence and recurrence rate of pulmonary embolism were 24.8% and 18.7%in children and young adults with nephrotic syndrome,respectively.The incidence of pulmonary embolism was different in different age groups,sex and pathological types of nephrotic syndrome.2.Membranous nephropathy and the level of proteinuria are independent risk factors for pulmonary embolism in children and young adults with nephrotic syndrome.3.D-dimer level at discharge and compliance with anticoagulant therapy（discontinuation of anticoagulant medication during anticoagulant period）are effective predictors of recurrent pulmonary embolism in children and young adults.For patients with primary pulmonary embolism,a follow-up period of 115 days has certain clinical value in predicting the recurrence of pulmonary embolism.