Are patients with bladder oversensitivity different from those with urodynamically proven detrusor overactivity in female overactive bladder syndrome?

Background To determine if there are clinical and urodynamic (UD) differences between female overactive bladder (OAB) patients with bladder oversensitivity (BO) and detrusor overactivity (DO) via a much lower filling rate. Methods In total, 205 patients with OAB symptoms were recruited for this study. During filling cystometry, the bladder was filled at a more “physiological” rate of 20 ml/min. All patients underwent a complete urogynecological evaluation including detailed history, physical examination, urinalysis, pad test for quantification of urine leakage, 3-day frequency-volume chart (FVC) documentation, and completion of a UD study. Results The overall incidence of BO was 34.2% and that of DO was 65.8%. The first desire to void (FDV) in patients with BO and DO were at filling of 117.47 ± 21.68 ml and 135.23 ± 22.88 ml, respectively (p < 0.05). Maximal cystometric capacities (MCC) in patients with BO and DO were recorded at 259.44 ± 33.87 ml and 265.32 ± 44.05 ml (p > 0.05). A receiver operating characteristic (ROC) curve was used to find the cut-off values of FDV for sensitivity and specificity in patients diagnosed with DO. Area under the curve (AUC) was 0.702 (p < 0.005, 95% confidence interval: 0.626–0.779) if FDV was determined as more than 127 ml. Patients with BO experienced significantly increased daytime urinary frequency and nocturia symptoms (<0.05). Patients with DO had a significantly higher prevalence of urgent urinary incontinence (p < 0.05). In this study, a higher FDV and higher body mass index (BMI) were correlating factors for OAB patients with DO after multiple logistic regression analysis. Conclusion Patients with BO seemed to be on a different spectrum compared to those with DO and also had different symptom-specific and associative factors. It was also found that FDV could be good predictive indicator for detecting DO at a low filling rate.