VURD syndrome--does it really preserve long-term renal function?

VURD (posterior urethral valves, unilateral vesicoureteral reflux and renal dysplasia) syndrome is the combination of persistent unilateral vesicoureteral reflux associated with an ipsilateral dysplastic, poorly functioning kidney in patients with posterior urethral valves. It was postulated that this syndrome may result in preservation of long-term renal function due to a pressure release pop-off mechanism. We determined the effects of VURD long-term renal outcomes.

We retrospectively reviewed the records of boys diagnosed with posterior urethral valves between 1983 and 2009 at a single pediatric tertiary hospital. Patients were divided into those with and those without VURD syndrome. The outcome of interest was renal impairment, defined as stage 3 or greater chronic kidney disease (glomerular filtration rate less than 60 ml/min/1.73 m(2)).

We identified 89 patients, of whom 23 (26%) had VURD. Median followup was 77 and 57 months in the VURD and nonVURD groups, respectively. Seven patients (30%) with and 26 (39%) without VURD had significant renal impairment. Survival analysis using a Cox proportional hazard model showed no association between VURD and renal impairment (HR 1.05, 95% CI 0.65-1.70). The main predictors of renal function were the creatinine nadir and patient age at diagnosis.

VURD syndrome does not seem to have a long-term protective effect on renal function.