Chronic kidney disease in classic bladder exstrophy following primary closure and then isolated bladder neck repair

We reviewed our data to evaluate changes in estimated glomerular filtration rates (eGFR) and chronic kidney disease (CKD) status in pediatric patients with classic bladder exstrophy (CBE) that have previously undergone staged repairs with primary closure followed by isolated bladder neck repair (BNR).

Medical records of patients with CBE (1986-2020) were retrospectively reviewed and included if the patient had undergone a staged repair without bladder augmentation and creatinine measurements were obtained prior to 18 years of age. Schwartz formula was used to calculate eGFRs and CKD status as determined by nephrology evaluations. Non-parametric statistical analysis was performed.

Twenty-two children (68% male) underwent primary closure (94% immediate neonatal) followed by BNR at median age of 5.1 years. At median follow-up after BNR of 16 years, 16 (73%) were augmented or diverted primarily for urodynamic deterioration or upper tract changes (81%). Mean preoperative eGFR was 109 ml/min/1.73 m² at which time no patient had a CKD classification based on eGFR criteria. Ninety-two percent had a decline in eGFR with mean change of -30 ml/min/1.73 m² (p < 0.001) observed prior to 18 years of age, corresponding to a -2.2 ml/min/1.73 m² (p = 0.02) annual rate of decline. A significant difference in eGFR between the two time points (before BNR and prior to age 18) was observed in male (p < 0.001) but not female (p = 0.29) patients. Prior to age 18, five patients met CKD criteria and one had CKD3+ at a median age of 14 years; all followed with a nephrologist.

Renal outcomes data following exstrophy repairs continue to be sobering, with nearly a 2-point annual decline in eGFR in patients undergoing staged repair including isolated BNR. We did note a significantly higher risk of renal functional decline during childhood in boys. More attention to the early surveillance of renal function following exstrophy repair is needed.