Post fulguration renal & bladder status (RBS grading) in prognostication of posterior urethral valves

Anatomical classifications of posterior urethral valves (PUV) have limited prognostic utility. We evaluated a Renal & Bladder Status (RBS) grading system, based on early post-treatment renal function and bladder morphology, in predicting long-term outcomes.

A retrospective review of 254 boys treated for PUV between 2003 and 2023 was performed. RBS-0 included non-classical/ suspected valves; RBS-1 classical PUV with preserved renal/bladder function (nadir creatinine <1 mg/dl and bladder contour normal); RBS-2 impaired but recoverable renal/bladder function (nadir creatinine <1 mg/dl and bladder contour improves) after fulguration; and RBS-3 persistent dysfunction (nadir creatinine >1 mg/dl or bladder contour abnormal/ persistent VUR) despite treatment. Primary outcome was progression to end-stage renal disease (ESRD); secondary outcome was valve bladder (VB). Kaplan-Meier survival and Cox proportional hazards models assessed predictors of ESRD.

ESRD occurred in 0% of RBS-0, 6.3% of RBS-1, 12.2% of RBS-2, and 51.7% of RBS-3 (p < 0.001). VB developed in 0%, 4.7%, 8.8%, and 41.3% respectively (p < 0.001). At 10 years, ESRD-free survival was 95% (RBS-0), 85% (RBS-1), 65% (RBS-2), and 35% (RBS-3) (log-rank p < 0.001). On multivariable Cox analysis, RBS-2 (HR 3.1, 95% CI 1.4-6.8), RBS-3 (HR 6.7, 95% CI 3.2-14.0), nadir creatinine > 1 mg/dL (HR 2.5, 95% CI 1.5-4.2), and high-grade VUR (HR 1.9, 95% CI 1.1-3.4) independently predicted ESRD, while age at presentation was not significant.

RBS grading, incorporating early renal and bladder recovery after treatment, provides prognostic information and enables early risk stratification in PUV. Larger prospective multi-center studies are warranted to validate RBS grading.