Study protocol for a parallel-group randomized controlled multi-center trial evaluating the additional effect of continuous ultrasound bladder monitoring in urotherapy for children with functional daytime urinary incontinence (SENS-U trial).

Background: Lower urinary tract dysfunction or functional urinary incontinence is a common condition with a prevalence up to 21% between 6 and 8 year-old children. It is associated with an impaired quality of life, lower self-esteem, and social stigmatization. Urotherapy is the first treatment of choice for functional daytime urinary incontinence (DUI) in children. Alarm therapy can be a part of urotherapy as it provides the child adequate feedback on wetting accidents. Current alarm systems notify either at a set interval or give a notification when wetting has already occurred to prompt the child to go to the toilet. These alarms do not teach the child the interpretation of the bladder sensation preceding wetting accidents. A new wearable bladder sensor, the SENS-U, recently became available. This is a relative small, wireless ultrasonic sensor, which continuously monitors bladder filling. The SENS-U is able to provide an alarm at the exact moment voiding is warranted. It facilitates the child to learn the sensation of bladder filling preceding voiding in an easier way, increasing the learning curve throughout treatment. Its additional effect in urotherapy on continence and cost-effectiveness is to be determined.

Methods/design: This is a multi-center clinical superiority parallel-group randomized controlled trial including a total of 480 children. Participants between 6 and 16 years of age with functional DUI in which urotherapy is offered as the next treatment of choice are eligible. Four centers, two academic hospitals, and two general care (peripheral) centers are participating. Participants will be randomized at a 1:1:1 ratio into three groups: urotherapy (care as usual), urotherapy with the SENS-U added for 3 consecutive weeks throughout the training, or urotherapy with a SHAM device for 3 weeks. The primary outcome is number of wetting accidents per week after 3 months of training, compared between the SENS-U and the SHAM device. The magnitude of the placebo effect will be assessed by comparing the results of the SHAM group versus the control (care as usual) group.

Discussion: To our knowledge, this is the first trial studying not only the effect but also the cost-effectiveness of alarm interventions as commonly added in urotherapy.

Trial Registration: ISRCTN44345202 . Registered on March 2022.