Relationship between Body Mass Index and Overactive Bladder in Women and Correlations with Urodynamic Evaluation

PURPOSE Overactive bladder (OAB) is a common condition. In women, studies have shown that the prevalence of OAB is positively related to increasing body mass index (BMI). Our objective was to define a relationship between BMI and OAB through correlation with urodynamic study (UDS). METHODS A prospective study was conducted. Ambulatory women aged 18 years or older who had symptoms of OAB for at least 3 months were enrolled. Patients answered a questionnaire, had their weight and height recorded, and underwent UDS. Patients were categorized into 3 groups as follows: group 1, BMI<25; group 2, BMI 25 to 29.9; and group 3, BMI≥30. RESULTS A total of 113 patients were examined (group 1, n=32; group 2, n=40; group 3, n=41). The patients' mean ages were 50, 55, and 59 years for groups 1, 2, and 3, respectively (P<0.05). Group 3 showed a significant increase in the incidence of subjective mixed leakage and the number of pads used compared with groups 1 and 2. No significant differences were seen among the groups in duration of symptoms, OAB V-8 score, or the incidence of subjective urgency or stress leakage. The UDS parameters of groups 1, 2, and 3 showed no statistically significant differences for most variables. Group 3 showed a significant increase in the incidence of urge leakage by UDS compared with group 2 only. CONCLUSIONS Increasing BMI was age related. A BMI≥30 showed a higher incidence of subjective urinary mixed leakage and pad use. UDS showed no significant correlation between OAB and any BMI category for most UDS parameters.