Relationship between voided volume and the urge to void among patients with lower urinary tract symptoms

<p><i>Objective.</i>The aim of this study was to explore the relationship between voided volume (VV) and urge to void among patients with lower urinary tract symptoms. <i>Material and methods.</i> Consecutive adult patients (aged 23–90 years) were enrolled, and completed a 24 h bladder diary and the Urgency Perception Scale (UPS). Patients were categorized as urgency or non-urgency based on the Overactive Bladder Symptom Score. The relationship between UPS and VV (based on the bladder diary) was analyzed by Spearman’s rho and proportional odds model. <i>Results.</i> In total, 1265 micturitions were evaluated in 117 individuals (41 men, 76 women; 56 individuals in the urgency and 61 in the non-urgency group). The mean (± SD) VV and UPS were 192 ± 127 ml and 2.4 ± 1.2 ml in the urgency group and 173 ± 124 ml and 1.7 ± 1.1 ml in the non-urgency group, respectively. Spearman’s rho (between UPS and VV) was 0.21 [95% confidence interval (CI) 0.13–029, <i>p</i> < 0.001] for the urgency group, 0.32 (95% CI 0.25–0.39, <i>p</i> < 0.001) for the non-urgency group, and 0.28 (95% CI 0.23–0.33, <i>p</i> < 0.001) for the total cohort. Urgency patients had higher UPS [odds ratio (OR) 3.1, 95% CI 2.5–3.8]. Overall, each additional 50 ml VV increased the odds of having a higher UPS with OR 1.2 (95% CI 1.2–1.3). The relationship between VV and UPS score was similar in both groups (<i>p</i> = 0.548 for interaction). <i>Conclusion.</i> Although urgency patients void with a higher UPS score, among both urgency and non-urgency patients there is only a weak correlation between VV and the urge to void. This suggests that there are factors other than VV that cause the urge to void.</p>