Post-Void Residual Urine Ratio (PVR-R) as a prognostic marker of chronic kidney disease in men with benign prostate hyperplasia

Introduction. Benign prostatic hyperplasia (BPH) and chronic kidney disease (CKD) are common conditions in elderly men that significantly affect quality of life. Despite the high prevalence of both pathologies, the relationship between them remains insufficiently understood. The traditional indicator – post-void residual volume (PVR) – is characterized by high variability and limited prognostic value. Therefore, the evaluation of the post-void residual urine ratio (PVR-R) is of particular interest as a potentially more sensitive and clinically relevant marker of lower urinary tract dysfunction and CKD progression. Objective. To assess the relationship between renal function and two urodynamic indicators – post-void residual volume (PVR) and post-void residual urine ratio (PVR-R) – and to compare their diagnostic utility in detecting CKD in men with benign prostatic hyperplasia. Materials and Methods. The study included 250 men with a confirmed diagnosis of BPH. All patients underwent ultrasound evaluation, laboratory assessment of renal function with estimated glomerular filtration rate (GFR) calculated using the CKD-EPI 2021 formula, and measurement of both PVR and PVR-R. Statistical analysis included Spearman correlation, ROC analysis with calculation of the area under the curve (AUC), and DeLong’s test for comparing prognostic models. Diagnostic thresholds for PVR-R were determined based on the Youden index. Results. PVR-R demonstrated a stronger negative correlation with eGFR (r = −0.69) compared to absolute PVR (r = −0.44), p < 0.001. In ROC analysis, the AUC for PVR-R was 0.77, compared to 0.63 for PVR (p < 0.001). The primary diagnostic threshold of PVR-R ≥60% provided 100% specificity but only 53% sensitivity. A screening threshold of PVR-R ≥25% yielded 86% sensitivity and 45% specificity. Thus, PVR-R proved to be a more sensitive and universally applicable indicator for the early detection of CKD than absolute residual urine volume. Conclusion. PVR-R demonstrates higher prognostic value in assessing CKD risk compared to absolute PVR. A threshold of ≥25% may be recommended for CKD screening in patients with symptoms of infravesical obstruction due to BPH.