High grade primary vesicoureteral reflux in boys: long-term results of a prospective cohort study.

PURPOSE: We evaluated the incidence of new permanent defects in boys with grade 4 or 5 vesicoureteral reflux, identified the risk factors for new permanent defects and reviewed the outcome of different management approaches by assessing the rates of urinary tract infection and new permanent defects.

MATERIALS AND METHODS: This prospective cohort study recruited patients from July 1995 to December 2006. Study inclusion criteria were male gender and grade 4 or 5 primary vesicoureteral reflux. Patients were divided into 2 groups by presentation mode, including group 1-prenatal reflux diagnosis and group 2-reflux diagnosed after investigation for urinary tract infection. All patients underwent initial renal (99m)Tc-dimercapto-succinic acid scan evaluation. Continuous antibiotic prophylaxis was given in all patients until at least age 2 years. Surgical correction for reflux was done in 28 patients and 76 were circumcised. Followup included renal (99m)Tc-dimercapto-succinic acid scan with renal ultrasound at age 12 months with repeat (99m)Tc-dimercapto-succinic acid scan at ages 2 and 4 years.

RESULTS: Included in our study were 151 patients (206 high grade refluxing renal units) with a median age at diagnosis of 1.9 months (range 1 day to 8.8 years). Median age at first followup was 14 months (range 3 months to 3 years) and at next followup it was 39 months (range 10 months to 11.3 years). There were 52 boys (34%) in group 1 and 99 (66%) in group 2. Baseline perfusion defects on initial renal (99m)Tc-dimercapto-succinic acid scan were identified in 41 of 52 boys (78.8%) in group 1 and in 74 of 99 (74.7%) in group 2. During followup new permanent defects developed in 8 of 52 boys (15%) in group 1 and in 10 of 99 (10%) in group 2. In 18 patients a total of 20 renal units showed new permanent defects, including 13 in kidneys with baseline perfusion defects and 7 in previously normal kidneys (p >0.9). In groups 1 and 2 combined infection developed before and after circumcision in 62 of 137 (45.2%) and 5 of 74 cases (6.7%), respectively (p <0.001). New permanent defects were seen in 4 of 76 circumcised (5.2%) and in 14 of 137 uncircumcised boys (10.2%) (p >0.3).

CONCLUSIONS: Baseline perfusion defects were seen on (99m)Tc-dimercapto-succinic acid scan at presentation in 115 of our 151 patients (76%) independent of presentation mode. New permanent defects developed in abnormal and previously normal kidneys, and were associated with urinary tract infection. Being circumcised was associated with fewer urinary tract infections and a lower incidence of observed new permanent defects (5.2% vs 10.2%).