Risk Factors for Renal Scarring and Deterioration of Renal Function in Primary Vesico-Ureteral Reflux Children: A Long-Term Follow-Up Retrospective Cohort Study

BACKGROUND AND PURPOSE The aim was to identify the risk factors for renal scarring and deteriorating renal function in children with primary vesico-ureteral reflux (VUR). MATERIALS AND METHODS Patients with primary VUR admitted to the National Cheng Kung University Hospital were retrospectively analyzed. The outcomes were renal scarring, assessed by technetium-99 m dimercaptosuccinic acid scanning, and renal function, assessed by estimated glomerular filtration rate. Univariate and multivariate models were applied to identify the corresponding independent predictors. RESULTS A total of 173 patients with primary VUR were recruited. The median age of VUR diagnosis was 10.0 months (IQR: 4.0-43.0 months). After adjusting for confounding factors, it was found that older age of VUR diagnosis (≥5 years vs. <1 year, adjusted OR = 2.78, 95% CI = 1.00-7.70, p = 0.049), higher grade of VUR (high grade [IV-V] vs. none, adjusted OR = 15.17, 95% CI = 5.33-43.19, p<0.0001; low grade [I-III] vs. none, adjusted OR = 5.72, 95% CI = 2.43-13.45, p<0.0001), and higher number of UTI (≥2 vs. 0, adjusted OR = 3.21, 95% CI = 1.06-9.76, p = 0.039) were risk factors for renal scarring, whereas a younger age of VUR diagnosis (≥5 years vs. <1 year, adjusted HR = 0.16, 95% CI: 0.05-0.51, p = 0.002), renal scarring (yes vs. no, adjusted HR = 3.66, 95% CI: 1.32-10.16, p = 0.013), and APN (yes vs. no, adjusted HR = 3.10, 95% CI: 1.05-9.14, p = 0.041) were risk factors for developing chronic kidney disease stage 2 or higher. CONCLUSIONS Our findings expand on the current knowledge of risk factors for renal scarring and deteriorating renal function, and this information can be used to modify the management and treatment of VUR.