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

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.

• Pelvic Floor Muscle Training (PFMT) (Behavioral): Supervised pelvic floor muscle training twice weekly for 8 weeks, including 3 sets of slow contractions (6-8 seconds) and 3 sets of fast contractions, posture education, breathing training, and daily home exercises.
• Behavioral Bladder Training Program (Behavioral): Structured behavioral program including timed voiding every 2 hours with weekly interval increases, suppression of urgency techniques, fluid optimization, reduction of bladder irritants, sleep hygiene measures, and lifestyle recommendations.
• Oxybutynin / Mirabegron (Standardized Pharmacotherapy) (Drug): Oxybutynin 5 mg every 12 hours as first-line therapy. Mirabegron 25-50 mg daily will be used in cases of intolerance or inadequate response. Medication use will be monitored and recorded.

Primary outcomes

• Change in ICIQ-SF Total Score from Baseline to Week 8 [Baseline and Week 8]: This measure evaluates the change in the International Consultation on Incontinence Questionnaire-Short Form (ICIQ-SF) total score between baseline and week 8. The ICIQ-SF assesses frequency, severity, and impact of urinary incontinence on quality of life. Scores range from 0 to 21, with higher scores indicating greater severity.

Secondary outcomes

• Change in ICIQ-LUTSqol Score from Baseline to Week 8 [Baseline and Week 8]: This measure evaluates the change in the International Consultation on Incontinence Questionnaire-Lower Urinary Tract Symptoms Quality of Life (ICIQ-LUTSqol) score between baseline and week 8. The questionnaire assesses the impact of urinary incontinence on daily activities, psychological well-being, and social functioning. Total scores range from 19 to 76, with higher scores indicating greater impairment.
• Change in Number of Urgency Urinary Incontinence Episodes per 24 Hours [Baseline and Week 8]: Change in the frequency of urgency urinary incontinence episodes per 24 hours, based on a 3-day bladder diary completed at baseline and week 8.
• Patient Global Impression of Improvement (PGI-I) at Week 8 [Week 8]: The PGI-I is a validated single-item global rating scale in which participants rate their improvement on a 7-point scale ranging from "very much better" to "very much worse." Lower scores indicate greater subjective improvement.
• Change in Number of Micturitions per 24 Hours [Baseline and Week 8]: Change in the total number of micturitions per 24 hours, based on a 3-day bladder diary completed at baseline and week 8.
• Change in Number of Urgency Urinary Incontinence Episodes per 24 Hours [Baseline and Week 8]: Change in the frequency of urgency urinary incontinence episodes per 24 hours, recorded in a 3-day bladder diary at baseline and week 8.
• Change in Number of Urgency Episodes per 24 Hours [Baseline and Week 8]: Change in the number of urgency episodes per 24 hours, obtained from a 3-day bladder diary at baseline and week 8.
• Change in Number of Absorbent Pads Used per 24 Hours [Baseline and Week 8]: Change in the total number of absorbent pads used per 24 hours, as documented in a 3-day bladder diary at baseline and week 8.
• Adherence to Assigned Intervention [Throughout the 8-week intervention period]: Proportion of participants achieving ≥80% adherence to the assigned intervention protocol, monitored through weekly checklists and session attendance logs.

Sex: Female, ages: 18 Years to any

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.