Purpose: The familial nature of vesicoureteral reflux (VUR) is well recognized and siblings of index patients with VUR are known to have an increased incidence of reflux. Reflux associated nephropathy is an important cause of hypertension and end stage renal disease. A major goal of screening siblings is to identify children who may be at risk of recurrent urinary tract infections and reflux nephropathy. With the lack of information on observational familial VUR studies, screening siblings for VUR remains controversial. We investigated the outcome of screening siblings in a large cohort of familial VUR.
Methods: In 1998, we were granted ethical approval from our institution to prospectively screen siblings of index patients with VUR. Parents of index patients with grade III to V VUR were asked permission to screen siblings who were younger than 6 years of age. VUR was diagnosed by voiding cystourethrography and renal scarring was evaluated by dimercaptosuccinic acid (DMSA) scan.
Results: 315 siblings (177 girls and 138 boys) in 272 families were enrolled in the study. Families with 2, 3, 4, and 5 affected children were 234, 34, 3 and 1, respectively. 257 (81.6%) siblings were younger than 3 years of age and 58 (18.4%) were 3 to 6 years old. There were a total of 503 refluxing units in 315 siblings. VUR was unilateral in 127 and bilateral in 188 siblings. The grade of VUR was grade I, II, III, IV, V VUR in 26, 38, 223, 195 and 21, respectively. 46% of the refluxing units were grade IV and V VUR in siblings younger than 3 years of age compared to 29% in siblings between 3 to 6 years old (p=0.004). DMSA scan revealed renal scarring in 22.5% of siblings compared to 38% in the index patients (p<0.001).
Conclusion: To our knowledge this is the largest prospective, observational study on sibling vesicoureteral reflux. The highest incidence of sibling VUR occurs in children under the age of 3 years. Siblings younger than 3 years of age have a significantly higher grade of VUR. This information may be useful when counseling parents about the risk of familial VUR.