Bladder Oversensitivity Is Associated with Bladder Outlet Obstruction in Men

Objective: The aim of this study was to assess whether there is an objective association between bladder outlet obstruction (BOO) and abnormal sensation parameters during filling cystometry in men. Methods: This was a prospective study. Consecutive patients referred for urodynamic examination were assessed for eligibility. Patients with permanent catheters, BPH related surgery, neurologic disease, or inability to complete the urodynamic study were excluded. All patients underwent full physical examination, as well as renal and bladder ultrasound including prostate size estimation, post void residual volume, and PSA, and they completed the International Prostate Symptoms Score (IPSS) questionnaire. The cohort was divided into obstructed and un-obstructed groups according to the Bladder Outlet Obstruction Index. Results: Ninety of the 115 patients recruited were obstructed (78%). Obstructed patients had significantly higher PSA, larger prostate volume, and higher IPSS. Detrusor overactivity did not differ between the two groups (45.6% vs. 48.1%, p = 0.83). First, normal, strong, and urgent desires to void were significantly lower in obstructed men: median (IQR) 118 (57–128) vs. 180 (80–200), 171 (85–257) vs. 227 (125–350), 221 (150–383) vs. 307 (180–477), and 276 (197–480) vs. 344 (280–535), respectively. First desire to void (FDV) had the highest area under the curve (AUC = 0.83, 95% CI = 0.76–0.90, p < 0.001) for predicting BOO with a Youden index of 0.78 at 140 mL. Conclusions: Our results suggest that there is a strong association between bladder oversensitivity and BOO in men. Men with FDV <140 mL had a significantly increased probability of being obstructed. These findings may shed a light on the pathophysiological connection between obstruction and enhanced afferent signaling from the bladder.