How do urinary diaries of women with an overactive bladder differ from those of asymptomatic controls?

To quantify clinically important differences in common diary variables between asymptomatic controls and women with symptoms of overactive bladder (OAB), controlling for the effects of age and race.

The 24-h urinary diaries of 49 women with symptoms of OAB were compared to those of age- and race-matched asymptomatic controls. Control subjects did not have a physical examination.

The 49 patients with OAB symptoms had a median (range) age of 51 (20-85) years, a body mass index of 25 (17-46) kg/m(2) and a parity of 2 (0-5). The median number of voids was significantly greater in women with OAB than asymptomatic controls (P < 0.001). The median value for mean voided volume was significantly lower in women with OAB than asymptomatic controls (P = 0.014). There was no difference in the maximum voided volume, total voided volume, daytime or night-time diuresis rates, voids per litre intake, or total fluid intake.

This preliminary study suggests that a median reduction of three voids/24 h and an increase of 70 mL in the mean voided volume might be clinically important goals in therapeutic trials for treating OAB symptoms. This remains to be confirmed by further studies linking improvements in quality of life and the overall impression of bladder health with these quantitative diary variable changes.