The association between an abnormal post-voiding urine volume and a lower estimated glomerular filtration rate in patients with type 2 diabetes with no voiding symptoms

Background/Aims: Diabetic cystopathy is a frequent complication of diabetes mellitus. This study assessed the association between the post-voiding residual (PVR) urine volume and diabetic nephropathy in type 2 diabetics with no voiding symptoms. Methods: This study investigated 42 patients with type 2 diabetes who were followed regularly at our outpatient clinic between July 1, 2008 and June 30, 2009. No patient had voiding problems or International Prostate Symptom Scores (IPSSs) ${\geq}12$. An urologist performed the urological evaluations and the PVR was measured using a bladder scan. A PVR > 50 mL on two consecutive voids was considered abnormal, which was the primary study outcome. Results: The mean patient age was $60{\pm}10years$; the IPSS score was $3.7{\pm}3.3$; and the diabetes duration was $11.9{\pm}7.8years$. Seven of the 42 patients (16.7%) had a PVR > 50 mL. The presence of overt proteinuria or microalbuminuria was associated with an increased risk of a PVR > 50 mL (p < 0.01). Patients with a PVR > 50 mL had a significantly lower estimated glomerular filtration rate (eGFR) compared with those with a PVR ${\leq}50mL$ ($59.2{\pm}27.1mL/min/1.73m^2$ vs. $28.7{\pm}23.3mL/min/1.73m^2$; p < 0.001). Multivariate logistic analysis revealed that a lower eGFR (odds ratio, 0.94; 95% confidence interval, 0.88 to 0.99; p = 0.04) was a significant risk factor for a PVR > 50 mL. Conclusions: Patients with diabetic nephropathy had a significantly higher PVR and a lower eGFR was associated with an abnormal PVR.