Study design

This was a randomized, double-blind, controlled, prospective single-center trial. The study protocol was approved by the ethics committee of the Second Hospital of Shandong University (Shandong, China), and registered at the Chinese Clinical Trial Registry (ChiCTR1800016280). All ongoing and related trials for this intervention have been registered. Written informed consent was provided from each participant.

The primary outcome of this study was the change in maximum bladder capacity measured by urodynamic tests. We used bladder capacity as the primary outcome because it was an objective and quantitative indicator. Secondary outcomes were the change of voiding frequency as recorded by voiding diaries, and improvement of symptoms as measured by the Overactive Bladder Symptom Score (OABSS) and Overactive Bladder Questionnaire (OAB-q).