Posterior urethral valves: Creatinine velocity, a new early predictor of renal insufficiency

Abstract

AimAntenatal screening has led to early detection of posterior urethral valves (PUV). However, despite early intervention, a proportion of children will develop chronic renal insufficiency. We studied the trend of serum creatinine following urinary tract decompression during the neonatal period in infants as a possible predictor of chronic renal insufficiency. MethodsPatients treated by endoscopic resection of posterior urethral valves between 1993 and 2004 were identified. From these, infants treated within the first 30days of life were identified. Serum creatinine values taken within the first 5days following initial drainage were recorded. A creatinine velocity for each patient was calculated by linear regression analysis. Creatinine was considered rising if velocity was >3μmol/L/day, or falling if velocity was <−3μmol/L/day. Chronic renal insufficiency was defined as CKD2 or higher. ResultsSixty-four neonates had decompression of the urinary tract. Of these, 16 had rising creatinine despite drainage, 10 had a plateau in creatinine level, and 36 had falling creatinine following drainage. Insufficient data were available in two to calculate creatinine velocity. Progression to renal insufficiency was significantly higher in patients with an initial rise in creatinine (62.5%) than in those with plateau creatinine (40%) or falling creatinine (8.6%) (P≤0.0005 by Fisher exact test). Mean follow-up was 9.2years. ConclusionsRising creatinine, even transiently, following urinary tract drainage in neonates with posterior urethral valves is significant and is a new and important indicator of long-term prognosis.