Predicting chronic kidney disease progression in children with posterior urethral valves.

Objective: Posterior urethral valves (PUV) leads to early chronic kidney disease (CKD) and renal failure in some children, while others may maintain preserved kidney function even into adulthood. Our goal was to assess the association between early imaging features and CKD progression in children with PUVs. We hypothesized that imaging features identified on PRUS and VCUG would be associated with CKD progression and could` be used in conjunction with nadir creatinine to predict future renal function.

Methods: Following individual institutional research board approvals, we performed a retrospective cohort study at two institutions. Electronic medical records were queried to identify all patients with a history of PUVs treated between 1990 and 2022. Children who presented in the first year of life and had their initial renal bladder ultrasound (RBUS) and voiding cystourethrogram (VCUG) performed within the first 90 days of life were included. The primary outcome, CKD progression, was defined as development of ESKD requiring dialysis or renal transplant or a decline in eGFR of greater than 50 %. Clinical variables of interest included: findings on initial RBUS (urinoma, cystic dysplasia, solitary kidney), vesicoureteral reflux on initial postnatal VCUG (degree and laterality), and nadir creatinine. Hazard ratios (HRs) were calculated from Cox proportional hazards regression for univariate and multivariable regression.

Results: Out of 537 patients with PUVs, 274 met our inclusion criteria. Median follow up was 5.84 years (IQR 2-10.2), and 55 patients (20 %) reached our primary outcome. Multivariable analysis showed the presence of any degree of vesicoureteral reflux, HR 3.1 (95 % CI 1.62-5.93), and nadir creatinine, HR 5.53 (95 % CI 4-7.64), were predictive of CKD progression When nadir creatinine within the first year of life is used as a sole predictor of CKD progression, the area under the receiver-operator curve was 0.89 (95 % CI 0.83-0.91).

Conclusions: This study confirms nadir creatinine as a strong predictor for CKD progression and ESKD in patients with PUVs. In our cohort, the presence of any degree or laterality of vesicoureteral reflux, was also a significant predictor for CKD progression.