Randomized Intervention for Children With Vesicoureteral Reflux (RIVUR)

Inclusion Criteria: * Age at randomization: at least 2 months, but less than 6 years of age. Note that children as young as 1 month were screened for the study. * Diagnosed first or second febrile or symptomatic UTI within 112 days prior to randomization * Presence of Grade I- IV VUR based on radiographic voiding cystourethrogram (VCUG) performed within 112 days of diagnosis of index UTI. * Appropriately treated index febrile or symptomatic UTI Exclusion Criteria: * Index UTI diagnosis more than 112 days prior to randomization * History of more than two UTIs prior to randomization * For patients less than 6 months of age at randomization, gestational age less than 34 weeks * Co-morbid urologic anomalies * Hydronephrosis, SFU Grade 4 * Ureterocele * Urethral valve * Solitary kidney * Profoundly decreased renal size unilaterally on ultrasound (based on 2 standard deviations below the mean for age and length) performed within 112 days after diagnosis of index UTI * Multicystic dysplastic kidney * Neurogenic bladder * Pelvic kidney or fused kidney * Known sulfa allergy, inadequate renal or hepatic function, Glucose-6-phosphate dehydrogenase deficiency or other conditions that are contraindications for use of TMP-SMZ * History of other renal injury/disease * Unable to complete the study protocol * Congenital or acquired immunodeficiency * Underlying anomalies or chronic diseases that could potentially interfere with response to therapy such as chronic gastrointestinal condition…