Congenital Renal Dysplasia Predicts End Stage Renal Disease in Children with Posterior Urethral Valves

Abstract

PURPOSE Obstructive uropathy secondary to posterior urethral valves (PUV) is still an important cause of end stage renal disease (ESRD) in children. The PURPOSE of this study is to analyze patients with PUV to determine risk factors that might be predictive for ultimate renal failure. MATERIAL AND METHODS A retrospective cohort study was performed of boys with posterior urethral valves from 1975 to 2005. Demographics, clinical details, and renal outcomes were abstracted from the medical record. Risk factors selected were high-grade VUR, nadir serum creatinine as a proxy for dysplasia, UTI, and severe bladder dysfunction requiring CIC. Risk factors were analyzed by univariate analysis and those achieving significance were then placed in a multi-variable logistic regression model. RESULTS A total of 142 patients were identified, half of whom presented in the neonatal period. 119 patients had sufficient records for evaluation. The mean follow-up was 7.2 years. The number of patients progressing to ESRD was 15 at a mean age of 8.1 years. Of these patients, 93% initially presented with VUR and 87% required CIC. An elevated nadir creatinine was seen in 80%. Multi-variable analysis revealed that an elevated nadir creatinine (O.R. 71) and the presence of bladder dysfunction (O.R. 8.9) were independent risk factors for ESRD. VUR was also associated with an increased risk of ESRD (O.R. 2.0) but was not statistically significant. Urinary tract infections were not associated with ESRD. CONCLUSIONS Patients with posterior urethral valves and severe bladder dysfunction whose nadir creatinine remains elevated are at risk for deterioration of the upper urinary tracts requiring renal replacement therapy. It is unclear if high-grade vesico-ureteral reflux at diagnosis may also be a poor prognostic sign or actually reno-protective. Further analysis is necessary to evaluate the effects of early aggressive bladder management on renal outcomes.