Does hydronephrosis predict the presence of severe vesicoureteral reflux?

We hypothesized that, in patients with vesicoureteral reflux (VUR) grade IV or V, hydronephrosis will likely be found, if the patient has a full bladder during the renal ultrasound examination. Eight hundred thirty-seven patients were included in the study. Patients ranged in age from <1 month to 18.7 years, with a median age of 1.3 years. Five hundred sixty-nine were female and 268 were male. In this retrospective study, each patient underwent a voiding cystourethrogram (VCUG) and a renal ultrasound examination. The presence of hydronephrosis and bladder filling status in 131 renal units with VUR grade IV or V was evaluated. Sensitivity and specificity for hydronephrosis to detect the presence of VUR grades IV and V were 60 and 92 %, respectively. Positive predictive value and negative predictive value were 74 and 87 %, respectively. Odds ratios for the relationship between hydronephrosis and severe VUR was significant (p = 0.046).

In patients with grade IV or V VUR, hydronephrosis will be observed in the presence of a full bladder. Therefore, a renal ultrasound could be considered a screening test to decide on performing a VCUG.