Long-Term fate of the upper urinary tract and ITS association with continence in exstrophy patients.

Introduction: Scarce data is available in literature about the upper urinary tract outcomes of patients with Exstrophy-Epispadias Complex (EEC). After bladder closure during childhood, EEC bladders can become hostile to the upper tracts after bladder by exposing them to high pressures, leading to hydronephrosis (HN) and kidney damage. Similarly, vesicoureteral reflux (VUR) may be present and increase the likelihood for pyelonephritis.

Objective: We sought to assess long-term upper urinary tract outcomes by evaluating renal function, HN and VUR; and to assess if upper urinary tract outcomes are associated with continence status.

Study Design: A retrospective review of EEC patients having ≥1 surger(y) (ies) at our institution from 1990 until 2019 was performed. Renal function was assessed by evaluating last available estimated glomerular filtration rate (eGFR) and creatinine values. HN was assessed on ultrasound and classified according to the SFU-classification. Patients with recurrent febrile urinary tract infections (UTI) or pyelonephritis underwent a voiding-cystourethrogram (VCUG) assessing VUR, graded following the 'International system of radiographic grading of VUR'. Descriptive and comparative statistical analysis were performed to assess if upper tract outcomes are associated with continence status.

Results: Forty-eight patients (75% male) had a median (IQR) follow-up of 18 (10-21) years. The table shows upper tract outcomes for the entire group and stratified by continence status. The median creatinine was 0.6 (0.2-0.9) mg/dL and median eGFR was 108 (72-160) mL/min/1.73 m [2]. In two patients (4.2%), HN (SFU-grade 2) was detected. Thirty-six patients (75%) underwent VCUG, revealing high-grade VUR (stage IV-V) in 8 patients (17%) and low-grade VUR (stage I-III) in 7 patients (15%). Continence was associated with a higher need for VCUG (p = 0.02) and a higher presence of VUR (p = 0.03).

Discussion: Renal function in EEC patients and non-EEC patients is comparable when age matched. Only 6% had low-grade HN which was asymptomatic. 17% had high-grade VUR, which is little compared to literature (40-70%). However, results in literature are described in patients with a 'one-stage' bladder closure, whereas some of our patients had a 'two-stage' procedure. A one-stage procedure creates higher bladder pressures resulting in higher VUR-rates. Statistical analysis has showed that continence is associated with a higher prevalence of recurrent febrile UTI's or pyelonephritis and of VUR.

Conclusions: No statistically differences were found between continent and incontinent patients concerning creatinine and eGFR value (p = 0.52 and p = 0.29), nor in the prevalence of hydronephrosis (p = 0.36). However, results of this study suggest that continent patients may portend a higher risk of upper tract deterioration with recurrent febrile UTI's and pyelonephritis due to VUR. Close monitoring of the upper tract status is therefore as important as focus on continence. Large-scale prospective studies defining renal function as well as pyelonephritis rates are needed to optimize the management of the upper tracts in EEC patients.