Risk factors for end stage renal disease in children with posterior urethral valves

Obstructive uropathy secondary to posterior urethral valves is an important cause of end stage renal disease in children. Early diagnosis and intervention to decrease bladder pressure and stabilize the upper urinary tract are important to delay or prevent the progression of renal insufficiency. We analyzed the records of patients with posterior urethral valves to determine risk factors that might be predictive of ultimate renal failure.

A retrospective cohort study was performed of children presenting to our institution with a diagnosis of posterior urethral valves from 1975 to 2005. Patient demographics, clinical background, laboratory and radiographic data, and renal outcomes were abstracted from the medical record. Potential risk factors were analyzed, such as high grade vesicoureteral reflux at diagnosis, nadir serum creatinine greater than 1.0 mg/dl, urinary tract infection and severe bladder dysfunction requiring clean intermittent catheterization. Risk factors were analyzed by univariate analysis with Fisher's exact test. Those achieving significance were placed in a multivariate logistic regression model and an OR was generated.

A total of 142 patients were identified, of whom half presented in the neonatal period. Of the patients 119 had sufficient records for evaluation and mean followup was 7.2 years. A total of 15 patients progressed to end stage renal disease. The mean interval from diagnosis to end stage renal disease was 8.1 years. Of these patients 93% initially presented with vesicoureteral reflux and 87% ultimately required clean intermittent catheterization. Increased nadir creatinine was seen in 80% of cases. Multivariate analysis revealed that increased nadir creatinine and bladder dysfunction were independent risk factors for end stage renal disease (OR 71 and 8.9, respectively). Vesicoureteral reflux was also associated with an increased risk of end stage renal disease (OR 2.0), although this was not statistically significant. Urinary tract infections were not associated with end stage renal disease.

Patients with posterior urethral valves and severe bladder dysfunction in whom nadir creatinine remains increased are at risk for upper urinary tract deterioration, requiring renal replacement therapy. It is unclear whether high grade vesicoureteral reflux at diagnosis may also be a poor prognostic sign. Further analysis is necessary to evaluate the effects of early aggressive bladder management on renal outcomes.