Objective To construct and verify the predictive value of a nomogram model for urinary tract infection by analyzing the influencing factors of urinary tract infection after dual-lens combined treatment of complicated kidney stones.Methods From March 2020 to January 2022, 115 patients with complicated kidney stones who were admitted to our hospital were selected and divided into infection group (32 cases) and noninfection group (83 cases) according to whether urinary tract infection occurred after operation. The gender, age, body mass index, diabetes mellitus, hypertension, coronary heart disease, previous extracorporeal shock wave lithotripsy(ESWL) history, preoperative urinary tract infection, renal dysfunction, stone size, operation time, staghorn stones, preoperative blood glucose level, and operation time were compared between the two groups. The univariate and multivariate logistic regression of urinary tract infection was carried out, and the selected influencing factors were fitted to the nomogram model by R software, and the receiver operating characteristic (ROC) curve was drawn to evaluate the predictive value of the nomogram model for urinary tract infection.Results There were no significant difference in gender, age, hypertension and coronary heart disease between the infection group and the non-infection group (all P>0.05). In the infection group, body mass index >24 kg/m2, diabetes mellitus, previous history of ESWL, preoperative urinary tract infection, renal dysfunction, stones >3.5 cm, operation time >100 min, staghorn stones, preoperative blood glucose >6.1 mmol/L, the percentages of intraoperative perfusion volume >30 L, intraoperative multi-channel and postoperative indwelling catheter >7 days were significantly higher than those in the non-infection group (all P<0.05). Univariate and multivariate logistic regression analysis showed that preoperative urinary tract infection, renal dysfunction, stone size, operation time, staghorn stones, preoperative blood sugar, and intraoperative perfusion volume were the most important factors in the urinary tract after double-endoscopy combined treatment of complicated kidney stones. Influencing factors of infection (all P<0.05). According to the logistic regression results, a nomogram model was drawn for the combined treatment of urinary tract infection after complicated renal calculi. The area under ROC curve of this model was 0.889 (95%CI:0.823～0.969). The average absolute error of the internal verification of the Bootstrap method was 0.020, and the prediction curve basically fitted the standard curve, indicating that the model prediction had a high accuracy. The results of the H-L goodness-of-fit test indicated that the predicted probability of the nomogram model had high consistency with the actual rate of urinary tract infection (χ2=1.968, P=0.121).Conclusions Preoperative urinary tract infection, renal dysfunction, stone size, operation time, staghorn stones, preoperative blood glucose, and intraoperative perfusion volume are the influencing factors of urinary tract infection after dual-endoscopy combined treatment of complicated kidney stones. The nomogram model established based on the above influencing factors can effectively predict the risk of postoperative urinary tract infection in patients.
