Kidney function outcomes in patients after complete primary repair of bladder exstrophy and penopubic epispadias: Results from the international bladder exstrophy consortium

Abstract

Historically, repair of bladder exstrophy (BE) is associated with compromise to the upper tracts; the single stage repair of BE was considered to exacerbate risks of kidney impairment. We aim to evaluate the risk of upper urinary tract deterioration or chronic kidney disease after the complete primary repair of exstrophy (CPRE). As part of the U.S.-India Multi-institutional Bladder Exstrophy Collaboration, we prospectively performed data collection on all patients managed at the Civil Hospital, Ahmedabad from 2010 to 2020. All patients who underwent primary or redo BE or primary penopubic epispadias (PE) repair using CPRE were included. Data on annual VCUG and DMSA, serum creatinine and cystatin-C, urinary albumin, and creatinine were aggregated. 72/104 patients who underwent CPRE at a median age of 1.7 years (IQR: 1.1-4.6) were included: 43(60%) patients with primary BE, 17(24%) with redo BE, and 12(17%) with primary PE. At a median follow-up of 4 years (IQR: 3-6), the overall median eGFR was 105 for BE, and 128ml/min for PE. 14(19%) patients had eGFR<90, and 22(31%) had microalbuminuria. 21(30%) patients had kidney scarring in DMSA and 31(44%) had VUR. Multivariate analysis showed that neither kidney scarring nor VUR could predict the presence of eGFR<90 or microalbuminuria. Of 72 patients, 2 (3%) patients had dry intervals >3h, 9 (13%) patients have dry intervals of 1-3h and 44 (61%) patients had dry intervals <1h during follow-up. We found that kidney function outcomes (i.e., eGFR and microalbuminuria) were not associated with continence status (p=0.3). In this series, we report a 5% incidence of CKD stage 2 or above that was not impacted by continence status. Furthermore, a 40% incidence of VUR and a 30% incidence of kidney scarring during follow-up was observed within this cohort, neither of which had a significant impact on renal function deterioration (i.e, decline in eGFR), but underscores the need for close kidney surveillance in children that have undergone bladder exstrophy repair. Modern CPRE technique for the repair of BE may increase the risk of kidney scarring in the intermediate-term follow-up, however, this finding does not correlate with low eGFR and presence of albuminuria inpatients. Therefore, close follow-up with serial kidney function measurements is warranted and necessary after CPRE.