Correlation Between Postvoid Residual Urine Volume and Lower Urinary Tract Symptoms as Measured by International Prostate Symptom Score in Patients With Benign Prostate Enlargement in Knh

Abstract

Background: Post Void Residual Urine Volume (PVR) is a widely used diagnostic tool for assessment of Benign Prostatic Enlargement (BPE) due to its procedural simplicity, availability and cost. However, its diagnostic accuracy in determining severity of Lower Urinary Tract Symptoms (LUTS) and threshold of what constitutes significant PVR has long been in contention. This study sought to establish the diagnostic accuracy and clinical value of PVR in determining severity of LUTS amongst BPE patients. Objective: To determine the correlation between PVR and severity of LUTS as measured by IPSS. Materials and Methods: The study was a cross-sectional analytical study where 67 patients undergoing treatment for BPE at Kenyatta National Hospital (KNH) Urology clinics were recruited into the study by consecutive sampling. Data collected was patient’s International Prostatic Symptom Score (IPSS) and PVR. The severity of LUTS was assessed and categorized with the validated IPSS score questionnaire into mild, moderate and severe LUTS. PVR was assessed using trans-abdominal bladder ultrasound after micturition. This was done as part of the routine Kidney Ureter and bladder ultrasound (KUB) ultrasound. The data obtained was entered into SPSS version 24 software for analysis. Bivariate analysis was done to determine the association between PVR and IPSS score and correlation between the two done using Spearman’s Rho correlation Test. A p value of 0.05 and confidence interval of 95% was used to determine significance of collected data. PVR was categorized into groups based on IPSS score to determine the PVR ranges for mild, moderate and severe IPSS. Receiver operating curves (ROC) were used to determine to cutXI off values for specific classifications of PVR based on IPSS score. Further bivariate analysis using Chi square test was done to assess association between categories of IPSS and categories of PVR. Results: 67 patients were recruited into the study. The average age was 66 years. PVR mean was 112mls with a range of 0- 1011mls. Average prostate volume was 69.4cc range 10- 235cc. Mean IPSS score was 18, range 0- 35. There was a positive correlation between IPSS and PVR; this was found to be statistically significant (p value <0.001). Using Receiver operating curve (ROC), PVR cutoff values for mild, moderate and severe LUTS were established at 24mls, 111mls and 345 mls respectively.