Isolated congenital hydronephrosis confers a higher risk for urinary tract infection in the first two years of life: evidence from a large database.

Introduction

Prenatal hydronephrosis (HN) is a common finding with prevalence of 2% at birth. There is limited data on UTI risk in infant with mild to moderate HN only, although it accounts to ~ 80% of infants with HN. There is also limited number of studies, based on large population studies.

Method

Data of all infants followed from birth to age 2 years at 3 regions of Israel by Clalit Health Services, was collected from their electronic medical record. Infants were divided into 3 categories according to their diagnosis at age of 6 months.

1) Infants with no urological diagnosis (control)

2) Infants with isolated diagnosis of HN (study)

3) Infants with nephrology/urologic diagnosis with our without HN (reference).

Prevalence of the diagnosis of UTI in first 2 years of life was compared between the 3 groups.

Results

Our cohort included 208,563 infants , (3,955) in the study group, and (1,784) in the reference group. Infants in the study group had 17.35% risk for being diagnosed with UTI by age 2 years, compared to 3.96% in the control group (RR of 4.38, 95% CI 4.08-4.71, p < 0.001). Infants in the reference group had a 32.23% risk of UTI by age 2 years, significantly higher than both the control group (RR 8.15, 95% CI 7.59-8.74) and the study group (RR 1.86, 95% CI 1.69-2.04).

Conclusion

Infants with congenital isolated hydroneprosis have a 4 times higher risk to develop UTI in the first 2 years of life compared to regular papulation.