Prenatal diagnosis of urinary tract dilation: Comparative prognostic value of APDRP and UTD grading systems

Purpose This study compares anteroposterior diameter of the renal pelvis (APDRP) and urinary tract dilation (UTD) prenatal grading systems for their accuracy in predicting postnatal outcomes. Materials and methods A retrospective multicenter study (June 2013–December 2024) included 211 patients classified prenatally using APDRP and UTD systems. Postnatal outcomes included spontaneous resolution, urinary tract infections (UTI), vesicoureteral reflux (VUR), urinary obstruction, and surgical need. ROC curve analysis was performed to assess predictive performance. Results 46 % of cases encountered spontaneous resolution; both classifications showed strong correlation with dilation severity (p < 0.001). For VUR endpoint, severe APDRP grade was associated with an OR of 4.24 (95%Cl 1.26–14.29, p = 0.02); UTD A2-3 had an OR of 3.12 (95%Cl = 1.02–9.58, p-value = 0.04). Regarding UTI, severe APDRP grade had an OR of 7.66 (95%Cl = 1.59–36.96, p-value = 0.01), while OR for UTD A2-3 was 5.59 (95%Cl = 1.25–25.01, p-value = 0.02). For obstructive uropathy, severe APDRP grade had an OR of 22.5 (95%Cl = 7.24–69.91, p-value <0.001); OR of UTD A2-3 was 8.65 (95%Cl = 2.96–25.28, p-value <0.001). Regarding need for surgery, severe APDRP grade had an OR of 22.10 (95%Cl = 7.73–63.11, p-value < 0.001), while UTD A2-3 had an OR of 11.41 (95%Cl = 3.93–33.14, p-value <0.001). ROC analysis showed that APDRP outperformed UTD in predicting spontaneous resolution (AUC 0.811 vs. 0.736), VUR (0.649 vs. 0.614), UTI (0.690 vs. 0.650), obstruction (0.799 vs. 0.686), andsurgery (0.792 vs. 0.705). Conclusions The APDRP system appears to be more accurate than UTD for the prediction of spontaneous resolution of dilation, urinary tract obstruction and need for surgical intervention.