To delineate the natural clinical trajectory and cumulative incidence of conservative management failure in children with primary vesicoureteral reflux (VUR) and a history of urinary tract infection (UTI), to identify independent risk factors, and to develop a prognostic nomogram for personalized risk stratification.

This retrospective study included 145 children with primary VUR and a history of UTI undergoing conservative management. We evaluated clinical data, maximum ureteral diameter (MUD), VUR grade, and immuneinflammatory markers. Multivariate Cox regression identified independent predictors of surgical intervention. A prognostic nomogram was constructed and validated using ROC curves, calibration plots, and decision curve analysis (DCA).

The cohort primarily consisted of infants (median age: 8.4 months). Over a median follow-up of 26.5 months, 38.6% of patients failed conservative management. Cumulative surgical rates were 22.1% at 1 year and 29.0% at 2 years. Platelet-to-lymphocyte ratio (PLR) >81.5 (HR = 2.763), MUD >7.5 mm (HR = 2.397), and high-grade VUR (HR = 2.091) were independent predictors of failure. The nomogram achieved AUCs of 0.782 (1-year) and 0.715 (2-year), with reasonable calibration and potential clinical net benefit.

During follow-up, 38.6% of children with VUR and a history of UTI underwent surgical intervention. Integrating PLR, MUD, and VUR grade, our nomogram may serve as an adjunctive tool for personalized risk stratification and for supporting shared decision-making regarding early surgical intervention, pending external validation.