Cutoff value of ureteral diameter ratio for predicting spontaneous resolution of vesicoureteral reflux

Purpose: The five-grade international scale for vesicoureteral reflux (VUR) has been the mainstay for describing VUR severity. The concept of the distal ureteral diameter to the L1-L3 vertebral body distance ratio has been validated. We validated the ureteral diameter ratio (UDR) for predicting VUR outcomes and determined the cutoff value for spontaneous resolution. Materials and Methods: This retrospective review included children with primary VUR and detailed serial voiding cystourethrograms (VCUGs) between March 2005 and December 2016. Patient characteristics, VUR grade, laterality, UDR, laboratory data, and follow-up results were collected. UDR was estimated as the largest distal ureteral diameter within the pelvis divided by the distance of the L1-L3 vertebral bodies. The primary outcome was the prediction of spontaneous VUR resolution. The secondary outcome was the determination of the cutoff value of UDR in the present cohort. Results: We recruited 101 children (59 boys and 42 girls) diagnosed as having primary VUR based on VCUGs at a mean age of 23.48 months. VUR resolved spontaneously in 31 (30.7%) children, 40 (39.6%) children had persistent disease, and 30 (29.7%) received surgical correction. In univariate analysis, laterality, VUR grade, and UDR were significantly associated with spontaneous resolution (P = 0.017, P = 0.026, and P = 0.001, respectively). Multivariate analysis revealed UDR as the prognostic factor for spontaneous VUR resolution (odds ratio, 4.167; P = 0.023). The area under the curve of UDR indicates that the prediction accuracy was 0.74. The optimal cutoff value for UDR in this study was 0.264 (sensitivity, 0.81 and specificity, 0.63). Conclusion: UDR is superior to the VUR grade for predicting spontaneous VUR resolution. Our findings add significant prognostic value for children with primary VUR. A cutoff value of 0.264 may assist with clinical assessment and future management.