First morning voided volume as a valuable tool for evaluating patients with overactive bladder

Abstract

Objective: This study aims to assess whether first morning voided volume (FMV) can be used as a tool to evaluate the symptom severity of patients with an overactive bladder (OAB). Materials and methods: We prospectively recruited patients with OAB symptoms from January 2009 to April 2010. All the patients completed a 3-day frequency–volume chart, including the measure of FMV and the Overactive Bladder Symptom Score (OABSS) questionnaire. All patients underwent either conventional pressure-flow urodynamic study or videourodynamic study. We analyzed the correlation between FMV, urodynamic studies, and symptom severity. Results: A total of 102 patients, including 43 men and 59 women, were recruited in the study. FMV was significantly correlated to the daily mean voided volume (p < 0.001) and cystometric capacity (p = 0.026). It was also negatively correlated to the subscores for daytime frequency (p = 0.013) and nighttime frequency (p < 0.001) on OABSS. However, no significant correlation was observed between FMV and the total score of OABSS. FMV showed a fair agreement with the maximum voided volume, which can predict small-volume bladders (kappa = 0.42 ± 0.08, p < 0.001), whereas the agreement between cystometric capacity and maximum voided volume was poor (kappa = 0.096 ± 0.05, p = 0.08). Conclusion: In patients with OAB, FMV can represent the severity of day- and nighttime frequencies. FMV was also shown to have a better ability in predicting small-volume bladders compared to the cystometric capacity. The measure of FMV may be helpful for patients who have poor compliance with regard to recording the frequency–volume chart.

Keywords

• first morning voided volume
• frequency–volume chart
• overactive bladder
• overactive bladder symptom scores