The Fate of Primary Nonrefluxing Megaureter: A Prospective Outcome Analysis of the Rate of Urinary Tract Infections, Surgical Indications and Time to Resolution

PURPOSE: We examined data on a cohort of patients with primary nonrefluxing megaureter to determine risk factors for febrile urinary tract infection, indications for surgery and time to resolution. MATERIALS AND METHODS: The records of patients younger than 24 months with primary nonrefluxing megaureter were prospectively captured from 2008 to 2015. Six a priori defined variables were studied, including gender, circumcision status, hydronephrosis SFU (Society for Fetal Urology) grade (low--1 and 2 vs high--3 and 4), continuous antibiotic prophylaxis use, ureteral dilatation (greater than 11 mm) and tortuosity. Univariate analyses and Cox hazard regression were done for febrile urinary tract infection risk factors. Resolution trends were analyzed using Kaplan-Meier curves. RESULTS: Mean ± SD age at the first clinic visit was 3.7 ± 4 months and mean followup was 26.3 ± 16.6 months. Of 80 patients with primary megaureter 66 (83%) had high grade hydronephrosis, 72 (90%) were male, 21 (26%) were circumcised and 40 (50%) had ureteral dilatation greater than 11 mm at baseline. Overall continuous antibiotic prophylaxis was prescribed to 34 patients (43%) and febrile urinary tract developed infection in 27 (34%) at a mean age of 5.8 months (median 3, range 1 to 24). Cox regression identified uncircumcised male gender (HR 3.4, 95% CI 1.1-10.7, p = 0.04) and lack of continuous antibiotic prophylaxis (HR 4.1, 95% CI 1.3-12.7, p = 0.01) as independent risk factors for febrile urinary tract infection. The 19 surgical patients (24%) had a larger mean ureteral diameter immediately preoperatively than those who did not require surgery (17 ± 5 vs 12 ± 4 mm, p <0.01). Kaplan-Meier curves showed that 85% of primary nonrefluxing megaureters that did not require surgery resolved in a median of 17 months. CONCLUSIONS: Febrile urinary tract infection developed in 34% of patients with primary nonrefluxing megaureter within the first 6 months of life. Circumcision and continuous antibiotic prophylaxis significantly decreased febrile urinary tract infection rates in those infants. Ureteral diameter 17 mm or greater was significantly associated with a higher rate of surgical intervention. Overall 76% of megaureters resolved during a median followup of 19 months.