Morphologic and urodynamic predictors of renal scarring in pediatric neurogenic bladder A cross-sectional study

This study aimed to evaluate the association of bladder diameter ratio (BDR), filling-phase detrusor pressure (Pdet), vesicoureteral reflux (VUR), age at initiation of clean intermittent catheterization (CIC), and estimated glomerular filtration rate (eGFR) with renal scarring in children with neurogenic bladder secondary to spinal dysraphism.

A retrospective review was conducted, including 133 patients followed between October 2023 and January 2025. Urodynamic studies and voiding cystourethrography (VCUG) were performed within a short interval of dimercaptosuccinic acid (DMSA) scintigraphy. BDR was measured on standardized anteroposterior VCUG images as the mean of two independent measurements. Correlation analyses, receiver operating characteristic (ROC) curves, and multivariable logistic regression were performed. Internal validation was conducted using bootstrap resampling, and model calibration and decision curve analysis were also assessed.

Renal scarring was identified in 55.6% of patients. Children with scarring had significantly higher BDR values (1.51±0.27 vs. 1.27±0.27, p<0.001). BDR demonstrated the strongest discrimination (area under the curve [AUC] 0.74, 95% confidence interval [CI] 0.64-0.83) and remained the variable most strongly associated with renal scarring in multivariable analysis (adjusted odds ratio [OR] 1.027, p=0.002). Although Pdet >32 cmH₂O and high-grade VUR were associated with scarring, their effects were attenuated after adjustment. eGFR was lower in scarred patients (117.3 vs. 130.4 mL/min/1.73 m², p=0.003), although its early discriminatory performance was limited.

BDR showed the strongest association with renal scarring among the evaluated morphologic and urodynamic parameters. Pdet and VUR provided supportive but overlapping risk information, whereas eGFR reflected later functional decline. Because the BDR and Pdet thresholds in this study were derived from the present dataset, they should be interpreted as exploratory and require external validation before being used clinically. Given its availability from routine VCUG imaging, BDR may assist in identifying higher-risk patients pending confirmation in independent cohorts.