Gender and vesico-ureteral reflux: a multivariate analysis.
The aim of this retrospective cohort study was to describe the characteristics of patients with primary vesico-ureteral reflux (VUR) with special attention to gender-specific differences. Between 1970 and 2004, 735 patients were diagnosed with VUR and were systematically followed in a single tertiary renal unit. The following variables were analyzed: race, age at diagnosis, clinical presentation, weight and height Z-score, unilateral/bilateral reflux, VUR grade, renal damage, severity of renal damage, constipation, and dysfunctional voiding. Comparison of proportion between genders was assessed by the chi-square test with Yates' correction. The logistic regression model was applied to identify independent variables associated with gender. A survival analysis was performed to evaluate VUR resolution. After adjustment, five variables remained independently associated with male gender at baseline: non-white race [Odds ratio (OR) = 1.98, 95% confidence interval (95% CI) 1.33-2.95, P=0.001], moderate/severe grade of reflux (OR=2.16, 95% CI 1.45-3.22, P<0.001), severe renal damage (OR=1.60, 95% CI 1.04-2.52, P=0.04), age at diagnosis <24 months (OR=1.79, 95% CI 1.23-2.60, P=0.002), and antenatal clinical presentation (OR=3.56, 95% CI 1.91-6.63, P<0.001). Follow-up data were available for 684 patients (93%). Median follow-up time was 69 months (range 6 months to 411 months). Girls had a greater risk of urinary tract infection (UTI) during follow-up than boys (OR=1.68, 95% CI 1.18-2.38, P=0.003). There was no difference in progression to chronic renal insufficiency (CRI) between boys (3.8%) and girls (2.4%) during this period of follow-up (OR=1.58, 95% CI 0.59-4.15, P=0.44). Gender as an isolated variable is a poor predictor of clinical outcome in an unselected series of primary reflux. Although boys had a more severe pattern at baseline, girls had a greater risk of dysfunctional voiding and recurrent UTI during follow-up.
Pediatric Nephro-urology Unit, Hospital das Clínicas, Federal University of Minas Gerais, Belo Horizonte, Brazil.
Jose Maria Penido
JM
Silva
Eduardo Araujo
EA
Oliveira
Jose Silverio Santos
JS
Diniz
Luis Sergio Bahia
LS
Cardoso
Renata Moura
RM
Vergara
Mariana Affonso
MA
Vasconcelos
Daniela Espirito
DE
Santo
D002675:Child, Preschool; D015331:Cohort Studies; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D007223:Infant; D008297:Male; D015999:Multivariate Analysis; D012189:Retrospective Studies; D012727:Sex Characteristics; D012737:Sex Factors; D014718:Vesico-Ureteral Reflux / Q000453:epidemiology*