Prognostic significance of distal renal tubular acidosis in posterior urethral valve

The prognostic significance of distal renal tubular acidosis (DRTA) in the development of overt nephropathy (ON) in children with posterior urethral valves (PUV) is not clear. This condition was studied prospectively in 22 children with posterior urethral valve (PUV), with normal renal function. Prior to surgery, the children with ON had a higher incidence of bilateral reflux (P=0.006), but the difference was not significant for age at surgery (P=0.31), duration of voiding symptoms prior to surgery (P=0.30), presence of DRTA (P=0.35) and bladder abnormalities (P=0.27), with none of these factors being significant on logistic regression analysis. At the end of the follow-up, after surgery, age at surgery (P≤0.0001), duration of voiding symptoms prior to surgery (P≤0.0003), persistent DRTA (P=0.0001) and persistent bladder dysfunction (P=0.02) after surgery were significantly higher in children with ON. On univariate logistic regression analysis, age at surgery (P=0.009), duration of voiding symptoms prior to surgery (P=0.01), persistent DRTA (P=0.002) and persistent bladder abnormalities (P=0.03) after surgery were significant for ON after surgery, but on stepwise multivariate logistic regression analysis only persistent DRTA (P=0.002) turned out to be significant. We conclude that persistent DRTA after surgery can predict overt nephropathy in children with PUV after surgery.