Predictive factors for resolution of congenital high grade vesicoureteral reflux in infants: results of univariate and multivariate analyses

Abstract

Purpose: We studied variables with impact on cessation of congenital high grade vesicoureteral reflux in univariate analyses and provide a multivariate model for prediction of reflux resolution.

Materials and methods: A total of 80 male and 35 female infants (median age 2.7 months) were included in this prospective observational study. Of the cases 71% were diagnosed after urinary tract infection and 26% after prenatal ultrasound. Reflux was bilateral in 70% of the patients and maximum grade was III in 16%, IV in 45% and V in 39%. The study protocol included repeat videocystometries, renal scintigrams, chromium edetic acid clearances and free voiding observations. Median followup was 36 months.

Results: Overall spontaneous reflux resolution, including cases downgraded to grade I to II, was 38%. Variables significantly negatively correlated to resolution were breakthrough febrile urinary tract infection, bladder dysfunction, higher grade of reflux at inclusion, renal abnormality, subnormal renal function, increased bladder capacity, residual urine and passive occurrence of reflux. Multivariate Cox proportional hazard model with stepwise selection identified 3 independent predictors--renal abnormality (hazard ratio 0.45, 95% CI 0.31-0.64, p <0.0001), bladder dysfunction (hazard ratio 0.43, 95% CI 0.29-0.64, p <0.0001) and breakthrough urinary tract infection (hazard ratio 0.38, 95% CI 0.18-0.78, p = 0.009). Performance of the model was evaluated by the receiver operating characteristic curve, with a calculated area under the curve of 83%.

Conclusions: Overall resolution rate in congenital high grade vesicoureteral reflux is high during the first years of life. By multivariate analyses renal abnormality, bladder dysfunction and breakthrough febrile urinary tract infection were identified as strong independent negative predictive factors for reflux resolution.