title: A New Grading System for the Management of Antenatal Hydronephrosis.
abstract: OBJECTIVE
  Standard clinical assessments do not predict surgical intervention in patients with a moderate degree of upper tract hydronephrosis. This study investigated whether combined measures of renal calyceal dilation and anteroposterior diameter (APD) of the renal pelvis at the first postnatal ultrasound better predict surgical intervention beyond standard assessments of the APD or Society of Fetal Urology (SFU) grading system.
  
  
  METHODS
  A retrospective cohort of 348 children with antenatal hydronephrosis followed from 2003 to 2013 were studied. Using Cox regression, the risk for surgery by APD, SFU, and combined grading on the basis of the first postnatal ultrasound was calculated. The predictive capability of each grading system for surgery was determined by calculating the positive likelihood ratio (LR+).
  
  
  RESULTS
  The combination of APD≥6-9 mm and diffuse caliectasis had a hazard ratio (HR) of 19.5 (95% confidence interval [95% CI], 3.94 to 96.9) versus 0.59 (95% CI, 0.05 to 6.53) for APD≥6-9 mm alone and a similar risk of 8.9 for SFU grade 3 (95% CI, 3.84 to 20.9). The combination of APD≥9-15 mm and diffuse caliectasis had an HR of 18.7 (95% CI, 4.36 to 80.4) versus 1.75 (95% CI, 0.29 to 10.5) for APD≥9-15 mm alone. The LR+ for surgery for diffuse caliectasis and APD≥6-9 mm was higher than for APD≥6-9 mm alone (HR=2.62; 95% CI, 0.87 to 7.94 versus HR=0.04; 95% CI, 0.01 to 0.32) and was higher for APD≥9-15 mm and diffuse caliectasis than APD≥9-15 mm alone (HR=2.0; 95% CI, 1.15 to 3.45 versus HR=0.14; 95% CI, 0.04 to 0.43). Both combined groups of moderate hydronephrosis (APD≥6-9 mm or ≥9-15 mm with diffuse caliectasis) had only slightly higher LR+ than SFU grade 3 (HR=1.89; 95% CI, 1.17 to 3.05).
  
  
  CONCLUSIONS
  These results suggest a grading system combining APD and diffuse caliectasis distinguishes those children with moderate degrees of upper tract hydronephrosis that are at higher risk of surgery.
authors.affiliation: Division of Nephrology, Department of Pediatrics, The Hospital for Sick Children.
authors.forename: Joana
authors.initials: J
authors.lastname: Dos Santos
authors.affiliation: Division of Nephrology, Department of Pediatrics, The Hospital for Sick Children, Division of Nephrology, Department of Medicine, University Health Network, and.
authors.forename: Rulan S
authors.initials: RS
authors.lastname: Parekh
authors.affiliation: Division of Nephrology, Department of Pediatrics, The Hospital for Sick Children.
authors.forename: Tino D
authors.initials: TD
authors.lastname: Piscione
authors.affiliation: Division of Urology, Department of Surgery, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Tarek
authors.initials: T
authors.lastname: Hassouna
authors.affiliation: Division of Urology, Department of Surgery, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Victor
authors.initials: V
authors.lastname: Figueroa
authors.affiliation: Division of Urology, Department of Surgery, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Paula
authors.initials: P
authors.lastname: Gonima
authors.affiliation: Division of Urology, Department of Surgery, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Isis
authors.initials: I
authors.lastname: Vargas
authors.affiliation: Division of Urology, Department of Surgery, The Hospital for Sick Children, University of Toronto, Toronto, Ontario, Canada.
authors.forename: Walid
authors.initials: W
authors.lastname: Farhat
authors.affiliation: Division of Nephrology, Department of Pediatrics, The Hospital for Sick Children, norman.rosenblum@sickkids.ca.
authors.forename: Norman D
authors.initials: ND
authors.lastname: Rosenblum
mesh_terms: D004108:Dilatation, Pathologic / Q000000981:diagnostic imaging; D005260:Female; D006801:Humans; D006869:Hydronephrosis / Q000000981:diagnostic imaging* / Q000601:surgery*; D007223:Infant; D007231:Infant, Newborn; D007670:Kidney Calices / Q000000981:diagnostic imaging* / Q000473:pathology; D007682:Kidney Pelvis / Q000000981:diagnostic imaging; D016013:Likelihood Functions; D008297:Male; D011181:Postnatal Care; D011237:Predictive Value of Tests; D016016:Proportional Hazards Models; D012372:ROC Curve; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D016216:Ultrasonography, Prenatal; D014517:Ureteral Obstruction / Q000150:complications / Q000601:surgery
keywords: antenatal hydronephrosis; congenital hydronephrosis; grading system; pelviectasis; ureteropelvic junction obstruction