Impact of Adjuvant Urinary Diversion versus Valve Ablation Alone on Progression from Chronic to End Stage Renal Disease in Posterior Urethral Valves: A Single Institution 15-Year Time-to-Event Analysis

Purpose: Long-term progression to end stage renal disease of valve ablation alone vs ablation followed by additional urinary diversion were compared among children with stage 3 chronic kidney disease due to posterior urethral valves. Materials and Methods: We performed a retrospective study of children with posterior urethral valves and stage 3 chronic kidney disease treated at a single institution between 1986 and 2011. The 3 treatment groups were classified as group 1-valve ablation alone, group 2-ablation plus subsequent vesicostomy and group 3-ablation followed by ureterostomies and/or pyelostomies. Baseline demographic characteristics were analyzed. Statistical analyses compared the incidence of time to end stage renal disease among the intervention groups using the Fisher-Freeman- Halton exact test and Kaplan-Meier analysis with the log rank test. Cox regression was used to determine predictors of end stage renal disease progression. Results: A total of 40 eligible patients were included in the study (group 1-14 patients, group 2-13 patients, group 3-13 patients). Baseline characteristics and post-intervention estimated glomerular filtration rate revealed no significant between-group differences. A statistically significant difference in progression to end stage renal disease was noted within 1 year after diagnosis of stage 3 chronic kidney disease among the treatment groups (log rank test p = 0.02). However, cumulative end stage renal disease incidence at 15-year followupshowed no statistical difference (log ranktest p = 0.628). Cox regressionanalysis determined that bilateral renal dysplasia (HR 2.76, 95% CI 1.21-6.30) and estimated glomerular filtration rate 60 ml/minute/1.73m 2 or greater after intervention (HR 0.23, 95% CI 0.09-0.61) were predictive of the likelihood of progression to end stage renal disease. Conclusions: Urinary diversion following valve ablation in children with stage 3 chronic kidney disease associated with posterior urethral valves may temporarily delay progression to end stage renal disease. However, no long-term benefit was noted from diversion in the ultimate incidence of end stage renal disease, suggesting that these interventions should be seen as a temporizing measure. Bilateral renal dysplasia and post-intervention estimated glomerular filtration rate are independent variables predicting overall chronic kidney disease progression.