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.

Clinical course of prenatally detected primary vesicoureteral reflux.

The purpose of this study was to report the clinical course of medium-long-term follow-up of children with prenatally detected vesicoureteral reflux (VUR). Between 1986 and 2004, 53 (41 males) children with VUR detected by investigation of prenatal hydronephrosis were followed up for a mean time of 66 months (range: 6-200 months). Newborns were investigated by ultrasound, voiding cystourethrogram (VCUG) and DMSA scan. Follow-up clinical visits were performed at 6-month intervals. After 24 months patients were investigated by conventional VCUG or direct isotope cystogram. Survival analysis was performed in order to evaluate the resolution of the reflux. Differences between subgroups (mild vs moderate/severe reflux) were assessed by the two-sided log rank test. Thirty (58%) infants presented bilateral VUR, for a total of 83 renal units. There was a predominance of severe reflux (54%). Renal damage was detected in 33.7% of the units on first renal scan. There was a significant correlation between severe reflux and renal damage scars (RR=3.4, 95% confidence interval [CI], 1.4-8, p=0.002). Forty-seven patients were treated with continuous prophylaxis. One patient developed systolic hypertension. Urinary tract infection occurred in 12 (25%) children conservatively managed. VUR resolution was evaluated in 56 renal units. Spontaneous resolution was observed in 25 units (45%). At 48 months after diagnosis, 75% of the cases of mild reflux (I-III) and 37% of severe reflux (IV-V) had resolved (log-rank, 5.6, p=0.017). There was an improvement of nutritional parameters between admission and the end of follow-up. In conclusion, the clinical course of prenatally detected VUR followed up on a medium-long-term basis is relatively benign. Our study corroborates the results obtained in other series of infants with reflux that emphasized the heterogeneity of this disorder.