Detrusor overactivity is missed by stopping urodynamic investigation at a bladder volume of 500 mL.

Objectives: To investigate whether detrusor overactivity (DO) is missed in a relevant percentage of patients if the urodynamic investigation (UDI) is stopped at a filling volume of 500 mL due to the fear of bladder overdistention, in patients with lower urinary tract symptoms and high bladder capacity.

Patients And Methods: A consecutive series of 1598 patients with a bladder capacity of >500 mL in the bladder diary undergoing UDI due to lower urinary tract dysfunction (LUTD) was prospectively investigated. UDI was performed according to Good Urodynamic Practices recommended by the International Continence Society. UDI was stopped at strong desire to void or in case of autonomic dysreflexia, vesico-uretero-renal reflux, bladder pain or discomfort.

Results: Of the 1598 patients (594 women, 1004 men), 1282 (80%) and 316 (20%) had neurogenic and non-neurogenic LUTD, respectively. Overall, DO was detected in 66% (1048/1598), in 71% (910/1282) with neurogenic and in 44% (138/316) with non-neurogenic LUTD. DO occurred in 16% (263/1598, 95% confidence interval [CI] 14.7-18.4%) only at a bladder volume >500 mL. This phenomenon was significantly (P < 0.001) more frequent in patients with neurogenic (18% [236/1282], 95% CI 16.4-20.6%) compared with non-neurogenic (9% [27/316], 95% CI 5.9-12.1%) LUTD.

Conclusions: In both neurological and non-neurological patients with high bladder capacity, we strongly recommend not to stop UDI at a bladder volume of 500 mL, as DO might be missed in a relevant percentage leading to inappropriate patient treatment.