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

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.

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.

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.

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.