title: VURD syndrome--does it really preserve long-term renal function?
abstract: OBJECTIVE
  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.
  
  
  METHODS
  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)).
  
  
  RESULTS
  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.
  
  
  CONCLUSIONS
  VURD syndrome does not seem to have a long-term protective effect on renal function.
authors.affiliation: Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Nathan A
authors.initials: NA
authors.lastname: Hoag
authors.affiliation: Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Andrew E
authors.initials: AE
authors.lastname: MacNeily
authors.affiliation: Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Hamidreza
authors.initials: H
authors.lastname: Abdi
authors.affiliation: Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada.
authors.forename: Victor
authors.initials: V
authors.lastname: Figueroa
authors.affiliation: Department of Urologic Sciences, University of British Columbia, Vancouver, British Columbia, Canada. Electronic address: kafshar@cw.bc.ca.
authors.forename: Kourosh
authors.initials: K
authors.lastname: Afshar
mesh_terms: D002648:Child; D006801:Humans; D007668:Kidney / Q000002:abnormalities* / Q000503:physiopathology; D008297:Male; D015999:Multivariate Analysis; D011379:Prognosis; D016016:Proportional Hazards Models; D012189:Retrospective Studies; D013577:Syndrome; D014521:Urethra / Q000002:abnormalities*; D014563:Urodynamics; D014718:Vesico-Ureteral Reflux / Q000503:physiopathology*
keywords: abnormalities; chronic; kidney; renal insufficiency; urethra; vesico-ureteral reflux