Survival and Kidney Outcomes of Children with an Early Diagnosis of Posterior Urethral Valves

Abstract

Background and objectives: Posterior urethral valve is the most common cause of bladder outlet obstruction in infants. We aimed to describe the rate and timing of kidney-related and survival outcomes for children diagnosed with posterior urethral valves in United States children's hospitals using the Pediatric Health Information System database.

Design, setting, participants, & measurements: This retrospective cohort study included children hospitalized between January 1, 1992 and December 31, 2006, who were in their first year of life, had a diagnosis of congenital urethral stenosis, and underwent endoscopic valve ablation or urinary drainage intervention, or died. Records were searched up to December 31, 2018 for kidney-related mortality, placement of a dialysis catheter, and kidney transplantation. Cox regression analysis was used to identify risk factors, and Kaplan-Meier survival analysis used to determine time-to-event probability. Subgroup survival analysis was performed with outcomes stratified by the strongest identified risk factor.

Results: Included were 685 children hospitalized at a median age of 7 (interquartile range, 1-37) days. Thirty four children (5%) died, over half during their initial hospitalization. Pulmonary hypoplasia was the strongest risk factor for death (hazard ratio, 7.5; 95% confidence interval [95% CI], 3.3 to 17.0). Ten-year survival probability was 94%. Fifty-nine children (9%) underwent one or more dialysis catheter placements. Children with kidney dysplasia had over four-fold risk of dialysis catheter placement (hazard ratio, 4.6; 95% CI, 2.6 to 8.1). Thirty-six (7%) children underwent kidney transplant at a median age of 3 (interquartile range, 2-8) years. Kidney dysplasia had a nine-fold higher risk of kidney transplant (hazard ratio, 9.5; 95% CI, 4.1 to 22.2).

Conclusions: Patients in this multicenter cohort with posterior urethral valves had a 5% risk of death, and were most likely to die during their initial hospitalization. Risk of death was higher with a diagnosis of pulmonary hypoplasia. Kidney dysplasia was associated with a higher risk of need for dialysis/transplant.

Podcast: This article contains a podcast at https://www.asn-online.org/media/podcast/CJASN/2019_10_03_CJN04350419.mp3.

Keywords: ESRD; United States; child; children; chronic renal disease; clinical nephrology; dialysis; humans; infant; kidney transplantation; mortality; mortality risk; obstructive uropathy; outcomes; pediatric kidney transplantation; pediatric nephrology; progression of renal failure; renal agenesis; renal dialysis; renal failure; renal function; renal progression; risk factors; survival; transplant outcomes.

Graphical abstract

Figure 1.

Study cohort construction and database query methodology. PHIS, Pediatric Health Information System database.

Figure 2.

Survival among children diagnosed with pulmonary hypoplasia is markedly different than those without the diagnosis. Five-year survival among those with pulmonary hypoplasia was 59% (95% CI, 51% to 68%) compared with 96% (95% CI, 96% to 97%) for those without pulmonary hypoplasia.

Figure 3.

Cumulative probability of a child undergoing an ESKD intervention (one-survival) was 7% (95% CI, 6% to 8%) at 1 year, increasing to 13% (95% CI, 11% to 15%) by 10 years of age.

Figure 4.

Cumulative probability of an ESKD intervention (one-survival) occurring for children with kidney dysplasia was significantly higher compared with those without kidney dysplasia (log-rank P<0.001). Five-year probability was 38% (95% CI, 32% to 43%) for children with kidney dysplasia compared with 6% (95% CI, 4% to 8%) for children without kidney dysplasia.