Purpose: Vesicoureteral reflux (VUR) is the most common urological anomaly in children. The association of VUR, febrile UTIs and renal parenchymal damage is well recognized. The aim of this study was to determine the prevalence and predictors of renal functional abnormalities in high grade VUR.
Methods: We retrospectively reviewed the medical records and dimercaptosuccinic acid (DMSA) scans of 774 consecutive children (301 males, 473 females) with primary high grade VUR (grade IV to V) seen at our institution between 1998 and 2011. Reflux was diagnosed by voiding cystourethrography and DMSA scan was performed to evaluate renal functional abnormalities. For multivariate analysis variables associated with renal functional abnormalities, such as history of presentation, age, gender and grade of VUR were analyzed in logistic regression model.
Results: 698 (90%) children had grade IV VUR and 76 (10%) had grade V VUR. Evidence of DMSA scan abnormalities consistent with reflux nephropathy was present in 291 (37.6%) children. Renal scarring was observed in 244 (35%) of the patients with grade IV VUR and 53 (70%) of the patients with grade V VUR. Univariate analysis revealed that older children (p<0.001, OR: 5.89), grade V reflux (p<0.001, OR: 4.09) and a history of preoperative bladder/bowel dysfunction (p=0.026, OR: 2.94) were significant predictors associated with renal functional abnormalities. Multivariate analysis showed that older children (p<0.001 OR: 4.95) and grade V reflux (p<0.001, OR: 3.45) were the most significant independent predictors associated with renal functional abnormalities.
Conclusion: Our study shows that there is increased risk of renal scarring in older children and grade V VUR. Furthermore patients with a history of bladder/bowel dysfunction are at greater risk of renal scarring. Early detection and treatment of high grade VUR may prevent renal parenchymal damage and limit progression of renal damage in congenital reflux nephropathy.