This tool calculates the PURK score—designed to risk-stratify boys with posterior urethral valve (PUV) who are at high risk of chronic kidney disease (CKD) stage ≥3. Developed at The Hospital for Sick Children (SickKids) in Toronto, Canada, the PURK score is a simple prognostic tool based on the child’s initial presentation variables.
For more details, see Kim et al. (2025). Development and international validation of a novel multivariate prognostic tool: posterior urethral valve risk of chronic kidney disease (PURK) score (DOI: 10.1007/s00467-025-06701-9).
Internal Validation: In a retrospective cohort of 120 patients (first presentation <12 months), the AUROC for predicting CKD stage ≥3 was 0.907 at 1-year and 0.873 at 5-year (institution 1). In the prospective internal validation cohort of 51 patients, AUROC for predicting CKD ≥3 was 0.897 (95% CI 0.795–0.998) at 1 year (38 patients) and 0.824 (95% CI 0.646–1.002) at 5 years (20 patients).
External Validation: Across 10 pediatric centers (Canada, United States, India, Australia), the AUROC was 0.844 (95% CI 0.790–0.898) at 1 year (245 patients) and 0.838 (95% CI 0.773–0.903) at 5 years (194 patients). Geographic subgroup analyses confirmed significant prognostic value (AUROC ranges: 0.865–0.932 for 1-year and 0.827–0.960 for 5-year predictions).