Association between chronic kidney disease and small residual urine volumes in patients with benign prostatic hyperplasia

Abstract

Aim: It has been well described that large residual urine volumes (≥300 mL) affect renal function in advanced benign prostatic hyperplasia (BPH). However, it is not clear whether small residual urine volumes (<100 mL) are related to renal function. The present study was performed to examine the association between chronic kidney disease (CKD) and the post-void residual urine volume (PVR) in BPH patients.

Methods: A cross-sectional study was performed in 160 consecutive BPH patients with PVR of less than 100 mL. We first determined the stage of CKD and compared the PVR in subjects with/without CKD. Next, we divided the subjects into three groups according to the extent of PVR (PVR < 12 mL, 12 mL ≤ PVR < 50 mL, 50 mL ≤ PVR < 100 mL) and compared the estimated glomerular filtration rate (eGFR) among these groups. Moreover, risk factors associated with CKD, including the presence of post-void residual urine, were explored by multiple logistic regression analysis.

Results: The PVR of the patients with CKD was significantly greater than that of the patients without CKD. The group with the normal PVR (group PVR < 12 mL) had a significantly higher eGFR compared with the other two groups. Multivariate analysis demonstrated that the presence of post-void residual urine (PVR ≥ 12 mL) was a significant and independent risk factor associated with the presence of CKD.

Conclusion: In BPH patients, the PVR of the patients with CKD was significantly greater than that of the patients without CKD and the presence of post-void residual urine (PVR ≥ 12 mL) was independently associated with CKD, indicating a close association between CKD and small residual urine volumes.