Abstract
BACKGROUND: Flexible ureteroscopy (FURS) is widely used for the treatment of upper urinary tract stones. However, postoperative sepsis remains a serious complication with potentially life-threatening consequences. This study aimed to develop and externally validate a nomogram for predicting the risk of sepsis following FURS. METHODS: A multicenter, retrospective observational cohort study was conducted, involving 1722 patients who underwent FURS. was conducted using data from 1722 patients, with a subset for model development and another for external validation. Key predictive factors such as gender, urine culture results, stone size, staghorn stones, preoperative albumin levels, and operative time were included in the model. Multivariate logistic regression analysis was used to identify independent predictors, and a nomogram was developed. RESULTS: Six independent predictors were identified: female gender, positive urine culture, stone size ≥ 2 cm, staghorn stones, preoperative albumin levels < 35 g/L, and operative time ≥ 60 min. The nomogram showed excellent performance, with C-index values of 0.88 (training), 0.87 (internal validation), and 0.85 (external validation). The model also demonstrated robust calibration and clinical utility through decision curve analysis. CONCLUSION: The nomogram developed in this study offers a simple and accurate tool for predicting sepsis risk following FURS. It can aid clinicians in making timely interventions and improving patient outcomes. Further validation and refinement in larger cohorts are needed.