BACKGROUND: Posterior urethral valve risk of chronic kidney disease (PURK) score is an internally and externally validated tool developed to predict patients who are at higher risk of CKD stages ≥3. It has been found to be robust and effective at predicting likelihood of CKD using clinical variables available at patient’s first presentation. We aim to evaluate whether there is potential for utilization of PURK score to predict need for renal replacement therapy in children.
METHODS: Our institutional posterior urethral valve (PUV) database was evaluated. PUV patients’ PURK scores were calculated using their presentation variables. Patients were divided by their renal replacement therapy status and compared. The utility of the PURK score for prediction of RRT was evaluated using receiver operating characteristics (ROC) curve. A Kaplan-Meier survival analysis was performed for time-to-event analysis, stratified by PURK score.
RESULTS: A total of 120 patients with complete data points were identified. There were 19 patients (16%) who progressed to RRT in our cohort, with a median follow up of 150 months. There was significant differences in the distribution of the PURK score between those who progressed to RRT and those who did not - 79% of RRT patients had PURK score of 3 or greater, compared to 10.9% of patients who did not progress to RRT (p<0.001). Area under ROC curve showed excellent prediction of 0.903 (95% CI 0.828-0.977; Figure 1). There was significant differences in survival analysis between patients with scores 0-2 (low risk), 3 (intermediate risk), 4-5 (high risk; log-rank p<0.0001; Figure 2).
CONCLUSIONS:
PURK score, while initially designed to predict progression of high-stage CKD, is also effective at predicting progression to RRT. This robust tool may allow clinicians to counsel the risk of progression to CKD and RRT to families on their first presentation for evaluation. However, further external evaluation of utility of PURK score in prediction of RRT is required for routine use for counseling surrounding progression to RRT.
