Development and Validation of a Nomogram for Predicting Urinary Tract Infection After Urodynamic Study

Area of Science:

• Urology
• Infectious Disease Epidemiology

Background:

• Antibiotic prophylaxis before urodynamic studies lacks international guideline consensus.
• Urinary tract infections (UTIs) are a potential complication of urodynamic studies (UDS).

Purpose of the Study:

• To develop and validate a nomogram predicting post-UDS UTI risk.
• To assess the clinical net benefit of selective antibiotic prophylaxis (AP) based on predicted risk.

Main Methods:

• Multivariable logistic regression to identify UTI predictors.
• Development of a user-friendly nomogram incorporating five clinical variables.
• Performance evaluation using ROC-AUC, Brier score, calibration, and precision-recall AUC.
• Decision curve analysis to assess clinical net benefit.

Main Results:

• The nomogram includes hydronephrosis, neurogenic lower urinary tract dysfunction, post-void residual volume ≥200 mL, age ≥70, and catheter use.
• The nomogram demonstrated fair discrimination (ROC AUC 0.7086) and good overall accuracy (Brier 0.0180).
• Decision curve analysis showed positive net benefit for selective AP at low clinical thresholds (<5%).

Conclusions:

• A simple, well-calibrated nomogram provides individualized post-UDS UTI risk estimates.
• The nomogram supports targeted AP for higher-risk patients, potentially reducing unnecessary antibiotic use.
• External validation is recommended for broader applicability.