Independent risk factors for renal damage in a series of primary vesicoureteral reflux: a multivariate analysis.
OBJECTIVE
The aim of this study was to investigate risk factors associated with different extents of renal parenchyma involvement in a paediatric series of primary vesicoureteral reflux (VUR).


METHODS
A total of 549 patients with VUR were analyzed. The variable of interest was renal scar, assessed by technetium-99m dimercaptosuccinic acid scan, and classified into three subtypes: focal scar, multiple cortical scarring and diffuse scars with a contracted renal unit. The multinomial regression model was applied to identify independent variables associated with each subtype of renal damage.


RESULTS
After adjustment, four variables remained independently associated with a contracted renal unit: reflux grades III-V (odds ratio (OR)=9.7; 95% confidence interval (CI) = 4.1-21.0), age at diagnosis (OR=3; 95% CI=1.6-5.1), unilateral reflux (OR=2.1; 95% CI=1.2-3.8), and male sex (OR=2; 95% CI=1.1-3.8). Two variables were associated with multiple scars: reflux grades III-V (OR=13.8; 95% CI=7.4-26.0) and age at diagnosis (OR=1.9; 95% CI=1.2-3.0). Two variables were associated with a focal scar: reflux grades III-V (OR=7.9, 95% CI CI=3.8-16.4) and male sex as a protective factor (OR=0.5; 95% CI=0.25-1.0).


CONCLUSIONS
Our findings suggest that the development of a contracted renal unit is probably due to congenital malformation, more commonly observed in male infants with high-grade reflux.
Pediatric Nephrourology Unit, Federal University of Minas Gerais (UFMG), Belo Horizonte, Brazil.
Jose Maria P
JM
Silva
Jose Silverio S
JS
Diniz
Eleonora M
EM
Lima
Sergio V
SV
Pinheiro
Viviane P
VP
Marino
Luis Sergio B
LS
Cardoso
Enrico A
EA
Colosimo
Ana C Simões E
AC
Silva
Eduardo A
EA
Oliveira
D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D006801:Humans; D007223:Infant; D007668:Kidney / Q000473:pathology; D007674:Kidney Diseases / Q000209:etiology*; D008297:Male; D015999:Multivariate Analysis; D012189:Retrospective Studies; D012307:Risk Factors; D014552:Urinary Tract Infections / Q000150:complications; D014718:Vesico-Ureteral Reflux / Q000150:complications*