Correlation of Prevoid and Postvoid Urine Volumes with International Prostate Symptom Score among Men with Lower Urinary Tract Symptoms

Abstract

Background: Males, 50 years and above, often suffer from lower urinary tract symptoms (LUTS).  International Prostate System Score (IPSS) is used clinically to assess LUTS. Urodynamic studies are the gold standard for its investigation, but are invasive, costly, time consuming and require expertise, and are not readily accessible, especially in low and middle income countries (LMICs). Transabdominal ultrasound comes in handy. It can be used to assess prevoid and postvoid urine volumes. Postvoid residual (PVR) urine volume is widely used in ultrasound evaluation of lower urinary tract symptoms (LUTS), but its interpretation without reference to prevoid urine volume (PrVR) may be limited. PrVR reflects bladder filling status and may provide important physiological context. This study aims to evaluate the relationship between PrVR, PVR, and IPSS in adult males with LUTS. Methodology: This was a prospective cross-sectional study carried out over a period of six months. Institutional ethical clearance and patients’ consent were obtained as required. Transabdominal ultrasound was used to measure PrVR and PVR. Symptom severity was assessed using IPSS. Data analysis was with the Statistical Package for Social Sciences (SPSS), version 20.0. Simple frequencies, measures of central tendencies and dispersion, paired sample t-tests and Pearson correlation tests were carried out. P-values < 0.05 were considered statistically significant. Assumptions of linearity was assessed. Effect sizes and 95% confidence intervals (CI) were reported where applicable. Results: A total of 273 subjects were studied, mean age was 67.2 years. The IPSS scores were: moderate (38.83%), severe (31.50%) and mild (29.67%). Prevoid urine volume was statistically greater than that of the postvoid (t = 21.356, p < 0.001), with a very large effect size (Cohen’s d = 1.29). The PrVR demonstrated a weak but statistically significant positive correlation with IPSS (r = 0.120, 95% CI: 0.002–0.234, p = 0.047); and PVR showed a moderate positive correlation with IPSS (r = 0.288, 95% CI: 0.175–0.392, p < 0.001).  Regression analysis demonstrated linear relationships with low coefficients of determination (PVV: R² = 0.0145; PVR: R² = 0.0832). Conclusion: PrVR and PVR show weak-to-moderate associations with symptom severity. While PVR demonstrates a relatively stronger relationship, both parameters explain only a small proportion of symptom variability, reflecting the multifactorial nature of LUTS. The PrVR provides important physiological context that enhances interpretation of bladder function. Incorporating PrVR improves the clinical relevance and interpretability of LUTS assessment.