Risk factors associated with chronic kidney disease in patients with posterior urethral valves without prenatal hydronephrosis

Abstract

Purpose: Postnatal diagnosis of posterior urethral valves continues despite the prevalence of prenatal ultrasound. We identified risk factors associated with chronic kidney disease in these children.

Materials and methods: We retrospectively reviewed the medical records of boys with posterior urethral valves with clinical presentations other than prenatal hydronephrosis. We recorded presenting symptoms, age at presentation, and preoperative hydronephrosis and/or vesicoureteral reflux. Chronic kidney disease was defined as previous renal transplantation, dialysis dependence or glomerular filtration rate less than 60 ml per minute/1.73 m(2) at last followup. We used univariate survival analysis with the log rank test of equality for categorical variables and Cox proportional hazard regression for continuous variables to identify risk factors associated with progression to chronic kidney disease.

Results: We identified 141 boys with posterior urethral valves with a postnatal presentation. Median age at presentation was 46 months (range 0.3 to 174). Febrile urinary tract infection in 28% of patients and voiding complaints in 50% were the most common presentations. A total of 12 patients (9%) progressed to chronic kidney disease up to 23 years after initial presentation. Preoperative bilateral hydronephrosis, increased hydronephrosis severity and bilateral vesicoureteral reflux were associated with progression to chronic kidney disease.

Conclusions: Approximately 10% of cases with postnatal presentation of posterior urethral valves progress to chronic kidney disease, sometimes decades after the initial presentations. Although all patients with posterior urethral valves should be counseled on the potential loss of renal function, children with risk factors warrant close followup into adulthood.