RESUMO
PURPOSE: Antibiotic prophylaxis is given to children at risk for urinary tract infection. However, evidence concerning its effectiveness in grade I to III vesicoureteral reflux is lacking. The objective of this study was to determine whether antibiotic prophylaxis reduces the incidence of urinary tract infection in young children with low grade vesicoureteral reflux. MATERIALS AND METHODS: Children 1 month to 3 years old with grade I to III vesicoureteral reflux were assigned randomly to receive daily cotrimoxazole or no treatment, and followed for 18 months. A urinary tract infection constituted an exit criterion. Infection-free survival rates were calculated using the Kaplan-Meier method and compared using the log rank test. RESULTS: A total of 225 children were enrolled in the study. Distribution of gender, age at inclusion and reflux grade were similar between the 2 groups. There was no significant difference in the occurrence of urinary tract infection between the 2 groups (17% vs 26%, p = 0.2). However, a significant association was found between treatment and patient gender (p = 0.017). Prophylaxis significantly reduced urinary tract infection in boys (p = 0.013), most notably in boys with grade III vesicoureteral reflux (p = 0.042). CONCLUSIONS: These data suggest that antibiotic prophylaxis does not reduce the overall incidence of urinary tract infection in children with low grade vesicoureteral reflux. However, such a strategy may prevent further urinary tract infection in boys with grade III reflux.