Urinary tract infections in children with prenatal hydronephrosis: A risk assessment from the Society for Fetal Urology Hydronephrosis Registry

Abstract

Risk factors for urinary tract infection (UTI) in children with prenatal hydronephrosis (PNH) are not clearly defined. Our study aim was to describe incidence and identify factors associated with UTI among a cohort of children diagnosed with PNH. Patients with confirmed PNH from four medical centers were prospectively enrolled in the Society for Fetal Urology (SFU) hydronephrosis registry between 9/2008 and 10/2015. Exclusion criteria included enrollment because of UTI, associated congenital anomalies, and less than 1-month follow-up. Univariate analysis was performed using Fisher's Exact test or Mann-Whitney U. Probability for UTI was determined by Kaplan-Meier curve. Median follow-up was 12 (IQR 4-20) months in 213 patients prenatally diagnosed with hydronephrosis. The majority of the cohort was male (72%), Caucasian (77%), and 26% had high grade (SFU 3 or 4) hydronephrosis. Circumcision was performed in 116/147 (79%) with known status, 19% had vesicoureteral reflux (VUR), and 11% had ureteral dilatation. UTI developed in 8% (n=18), 89% during their first year of life. Univariate analysis found UTI developed more frequently in females (p<0.001), uncircumcised males (p<0.01), and the presence of parenchymal renal cyst (p<0.05). Logistic regression found renal cyst to no longer be significant, but female gender a significant risk factor for development of UTI (p<0.001). Regression analysis stratified by gender found neither hydronephrosis grade nor parenchymal renal cyst to be significant risk factors for UTI development among females. However, hydronephrosis grade and circumcision status were significant risk factors for development of UTI among males (p<0.05 and p<0.01, respectively). Identification of factors associated with UTI in patients with PNH is still progressing; however, several observational studies have identified groups that may be at increased risk of UTI. Use of prophylactic antibiotics (PA), degree of kidney dilation, gender, and circumcision status all have been reported to have some degree of impact on UTI. A previous study identified risk factors for UTI as female gender, uncircumcised status, hydroureteronephrosis, and VUR, and reported that prophylaxis provided a protective effect on prevention of UTI. Our data mirror those in some respect, identifying an association of UTI with female gender and, among males, uncircumcised status, and high grade hydronephrosis. However, we were unable to demonstrate an association between UTI and the use of PA, presence of VUR, dilated ureter, or renal duplication in this observational registry.