Long-Term Kidney Outcomes in Children with Posterior Urethral Valves A Population-Based Cohort Study

Key PointsAmong 727 children with posterior urethral valves, 32% had major adverse kidney events (death, kidney failure, or CKD) over a median of 14.2-year follow-up.Children with posterior urethral valves were at substantially higher risks of kidney failure, CKD, and hypertension than the general population.This justifies close kidney health surveillance among children with posterior urethral valves and optimized transitions to adult urologic care. BackgroundPosterior urethral valves represent the most common cause of lower urinary tract obstruction in male infants (approximately 1/4000 live births). Long-term kidney outcomes of posterior urethral valves remain uncertain. We aimed to determine the time-varying risk of major adverse kidney events (MAKE) following children with posterior urethral valves into adulthood. MethodsA population-based retrospective cohort study of all male children (<2 years) diagnosed with posterior urethral valves between 1991 and 2021 in Ontario, Canada. Comparator cohorts were (1) male general population and (2) male children with pyeloplasty (both <2 years). The primary outcome was MAKE (death, long-term KRT [dialysis or kidney transplant], or CKD). Time to MAKE was analyzed using multivariable-adjusted Cox proportional hazards models. We censored for provincial emigration or administrative censoring (March 31, 2022). ResultsWe included 727 children with posterior urethral valves, 855 pyeloplasty comparators, and 1,013,052 general population comparators. The median follow-up time was 16.6 years (Q1-3, 8.6-24.5) overall. Throughout follow-up, 32% of children with posterior urethral valves developed MAKE versus 1% of the general population and 6% of pyeloplasty comparators. Their adjusted hazard ratio for MAKE was 36.6 (95% confidence interval, 31.6 to 42.4) versus the general population. The risk of developing MAKE declined over the first 5 years after posterior urethral valves diagnosis but remained elevated for >30-year follow-up. Children with posterior urethral valves were also at higher risk of death, CKD, long-term KRT, hypertension, and AKI than the general population or pyeloplasty comparators. ConclusionsChildren with posterior urethral valves are at higher risk of adverse long-term kidney outcomes well into adulthood.