Purpose: The aim of this study was to identify risk factors for urinary tract infection during followup of children with fetal renal pelvic dilatation.
Material and methods: A total of 192 patients were diagnosed with isolated renal pelvic dilatation between 1999 and 2006 and were prospectively followed. After initial clinical and imaging evaluation ultrasound, clinical examination and laboratory reviews were scheduled at 6-month intervals. The event of interest was incidence of episodes of febrile urinary tract infection. A survival analysis was performed to identify variables significantly associated with the event. Cox model was applied to identify variables that were independently associated with urinary tract infection.
Results: A significant uropathy was diagnosed in 78 infants (41%). Median followup was 24 months. During followup urinary tract infection occurred in 27 (14%) of the 192 children. The incidence rate of urinary tract infection decreased from 7.2 episodes per 1,000 person-months in the first year of life to 1.4 after the third year. By survival analysis the cumulative incidence of urinary tract infection for the whole series was estimated at 8% at age 12 months, 13% at 24 months and 21% at 36 months. After adjustment 2 variables were independent predictors of urinary tract infection during followup-female gender (RR 1.4, 95% CI, 1.04 to 1.8, p = 0.02) and presence of uropathy (RR 4.6, 95% CI, 1.8 to 11.3, p = 0.001).
Conclusions: According to our findings, in a cohort of prenatal hydronephrosis girls with vesicoureteral reflux or urinary tract obstruction had a higher risk of urinary tract infection during followup.