A nomogram for predicting renal function recovery after robotic-assisted ureteral reconstruction: development and...

Area of Science:

• Urology
• Nephrology
• Medical Informatics
• Machine Learning in Medicine

Background:

• Ureteric obstruction can impair renal function.
• Predicting renal recovery post-surgical repair is crucial for patient management.
• Developing accurate predictive models aids clinical decision-making.

Purpose of the Study:

• To develop and validate predictive models for significant renal function recovery after ureteric obstruction repair.
• To compare a traditional Multivariable Logistic Regression model with a Machine Learning-based LASSO Regression Model.
• To present the most practical model as a clinical nomogram for predicting renal recovery.

Main Methods:

• Retrospective analysis of 100 adult patients undergoing surgical repair for unilateral ureteric obstruction.
• Development of a Multivariable Model (backward stepwise regression) and a LASSO Model (least absolute shrinkage and selection operator regression).
• Performance evaluation using discrimination (AUC), calibration (calibration curve), and clinical utility (Decision Curve Analysis), with internal validation via bootstrap resampling.

Main Results:

• The Multivariable Model identified four predictors: age, preoperative ipsilateral GFR, renal atrophy, and SFU Grade 4.
• The LASSO model selected 12 variables, showing slightly higher discrimination (AUC 0.841 vs. 0.827) and validated AUC (0.779 vs. 0.776).
• Despite marginal statistical advantages of the LASSO model, the 4-variable Multivariable Model offered superior balance of accuracy, interpretability, and clinical utility, leading to its selection for nomogram development.

Conclusions:

• A robust 4-variable nomogram was developed for predicting renal recovery after ureteric obstruction repair.
• The simpler Multivariable Model demonstrated excellent calibration and comparable clinical utility to the more complex LASSO model.
• The developed nomogram serves as a valuable tool for patient counseling and surgical decision-making in cases of ureteric obstruction.