Behavioral Interventions Versus Pelvic Floor Muscle Therapy as Adjuncts to Anticholinergic Pharmacotherapy for Urgency Urinary Incontinence: A Non-Inferiority Trial

Non-Inferiority Randomized Clinical Trial Comparing Behavioral Therapy Plus Pharmacotherapy Versus Pelvic Floor Muscle Training Plus Pharmacotherapy in Women With Urgency Urinary Incontinence

Urgency urinary incontinence (UUI) is a common condition that significantly affects women's quality of life. Pharmacotherapy is often used as first-line treatment, but its effectiveness can be limited unless combined with non-pharmacological interventions. Pelvic floor muscle therapy (PFMT) is widely recommended; however, access to specialized physiotherapy services is limited in many low-resource settings such as Nicaragua. Behavioral interventions-including bladder training, fluid control, avoidance of bladder irritants, and sleep-hygiene strategies-represent a low-cost alternative, but direct comparative evidence against PFMT is limited.

This randomized, controlled, non-inferiority clinical trial will compare two adjuvant strategies combined with standard anticholinergic pharmacotherapy (oxibutinine):

1. Pelvic floor muscle therapy (PFMT), and
2. Behavioral interventions (bladder training and lifestyle modification).

Eighty adult women with urgency urinary incontinence or mixed incontinence with urgency-predominance will be randomized 1:1. The intervention period is 8 weeks, with assessments at baseline, week 4, week 8, and an exploratory follow-up at week 12.

The primary outcome is the change in the International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF) score from baseline to week 8. A non-inferiority margin of 3 points will be applied. Secondary outcomes include episodes of urgency/incontinence per 24 h, ICIQ-LUTSqol scores, patient-reported global improvement (PGI-I), adherence, and adverse events.

This study aims to determine whether behavioral interventions are not inferior to PFMT as adjuncts to pharmacotherapy, potentially offering a feasible and more accessible therapeutic alternative for women with UUI in resource-limited healthcare environments.

Urgency urinary incontinence (UUI) is highly prevalent among women and is associated with substantial psychosocial, functional, and economic consequences. Although anticholinergic medications are commonly used, their effectiveness is often improved when combined with adjunctive non-pharmacological interventions. Pelvic floor muscle therapy (PFMT) has strong evidence supporting its use; however, its implementation requires trained personnel, scheduled sessions, and specialized infrastructure, which may not be accessible in low-resource settings.

Behavioral interventions-including bladder training, fluid management, avoidance of bladder irritants, dietary modifications, bowel regulation, and sleep-hygiene measures-represent a practical and low-cost alternative. Despite their clinical utility, there is limited evidence from randomized trials directly comparing behavioral interventions to PFMT when used as adjuncts to pharmacotherapy.

This study is a randomized, controlled, non-inferiority trial conducted at a national reference hospital in Nicaragua. The trial will enroll 80 adult women (≥18 years) diagnosed with UUI or mixed urinary incontinence with urgency predominance. Participants will be randomized in a 1:1 ratio to receive either (1) PFMT plus pharmacotherapy or (2) behavioral interventions plus pharmacotherapy. Oxibutinine (5 mg every 12 hours) will be used as the standard pharmacological agent, with mirabegron available as second-line therapy when intolerance occurs.

The intervention period lasts 8 weeks. PFMT includes supervised sessions twice per week plus a structured home-exercise program. Behavioral interventions include individualized bladder-training schedules, fluid-intake monitoring, avoidance of irritants, lifestyle counseling, and sleep-hygiene strategies. Adherence will be monitored at weeks 4 and 8.

The primary outcome is the change in ICIQ-SF score from baseline to week 8, with non-inferiority defined as an upper bound of the 95% confidence interval below 3 points. Secondary outcomes include ICIQ-LUTSqol, episodes of urgency and incontinence (3-day bladder diary), PGI-I, adherence to interventions, and adverse events. Week 12 assessments will explore persistence of clinical benefit.

This study is designed to generate locally applicable evidence to inform clinical practice in settings where PFMT availability is limited. Demonstrating non-inferiority of behavioral interventions could support more accessible and cost-effective management strategies for women with UUI.

Inclusion Criteria

• Women aged ≥18 years.
• Symptoms of urgency urinary incontinence (UUI) or mixed urinary incontinence with predominance of urgency, with duration ≥3 months.
• Clinical diagnosis of UUI based on history, physical examination, and a 3-day bladder diary.
• Predominance of urgency defined as: at least 50% of total recorded episodes in the bladder diary correspond to urgency (with or without leakage).
• Baseline ICIQ-SF score ≥6.
• Ability to attend scheduled visits and comply with assigned intervention.
• Signed informed consent.

Exclusion Criteria:

• Pure stress urinary incontinence.
• Mixed urinary incontinence with predominance of stress defined as: more than 70% of episodes in the 3-day bladder diary are triggered by physical effort.
• Symptomatic advanced pelvic organ prolapse (POP-Q stage ≥III).
• Active or recent urinary tract infection (within the last 7 days).
• Prior use of anticholinergics or β3-agonists that cannot be discontinued for a 14-day washout period.
• Pregnancy or breastfeeding.
• Neurological or psychiatric disorders affecting bladder function, record-keeping, or adherence.
• Cognitive or functional difficulty preventing understanding or completion of study procedures.