Abstract

Background: Posterior urethral valve (PUV) is the most common cause of lower urinary tract obstruction in male children. PUV has a broad spectrum of clinical presentations and can develop into renal failure at varying ages. Many previous studies reported serum creatinine to be a useful prognostic factor and a practical method for predicting long-term renal outcome, but the cut-off value is still unclear. The authors aimed to identify the optimum cut-off value of initial creatinine (iCr) as a prognostic factor for CKD, and to estimate the renal failure-free survival (RFFS) rate in PUV patients.

Methods: Male pediatric patients who were diagnosed with PUV at Siriraj Hospital (Bangkok, Thailand) during January 2005 to December 2016 were retrospectively reviewed. Statistical methods, including receiver operating characteristic (ROC) curve analysis, Kaplan-Meier method, log-rank test and Cox proportional hazards regression were used. Statistical significance was defined as p<0.05.

Results: Of the 69 patients identified, 41 were included. The median age at intervention was 240 days (range: 2-3,240). CKD was found in 48.7% at the last follow-up, the optimal cut-off value for initial creatinine associated with CKD was 0.7 mg/dL, and median renal failure-free time was 57 months. Multivariable analysis revealed initial creatinine to be the only independent predictor of long-term renal outcome in PUV patients.

Conclusion: Initial creatinine was found to be an independent predictor of long-term renal outcome in PUV patients. An initial creatinine cut-off value of 0.7mg/dL or greater is significantly associated with high risk of developing CKD (adjusted HR: 4.4, 95% CI: 1.4-13.8; p=0.011).