Comparing the Effect of Two Types of Pelvic Floor Muscle Stimulation Devices to Improve Symptoms of Urinary Incontinence in Women.

This prospective, randomized, parallel-group, non-inferiority clinical trial will evaluate whether electromagnetic pelvic-floor stimulation delivered using the StarFormer® chair is non-inferior to standard pelvic-floor electrostimulation combined with biofeedback in women with mixed urinary incontinence (MUI).

The study will enroll 58 women, with 29 participants allocated to each treatment group.

Randomization will be performed in a 1:1 ratio and stratified according to the predominant type of incontinence-urgency-predominant, stress-predominant, or balanced MUI-and baseline symptom severity.

Eligible participants will be women aged 18 years or older with symptoms of both stress urinary incontinence (SUI) and urgency urinary incontinence (UUI) lasting for at least three months.

The diagnosis of MUI will be confirmed by a baseline three-day bladder diary documenting at least one SUI episode and one UUI episode.

Participants must be treatment-naive or have received no recent pharmacological or supervised physical treatment for urinary incontinence. Women with active urinary tract infection, advanced pelvic organ prolapse, pregnancy, recent childbirth, major neurological disease affecting bladder function, previous anti-incontinence surgery, clinically relevant voiding dysfunction, or contraindications to electromagnetic stimulation will be excluded.

Participants in the investigational group will receive electromagnetic chair therapy, while those in the control group will undergo standard electrostimulation with biofeedback.

Both interventions will consist of two sessions per week for six weeks, resulting in a total of 12 treatment sessions. Treatment intensity will be set at the maximum level tolerated by each participant, and session duration, intensity, interruptions, adherence, and any adverse events will be documented. Attendance at a minimum of 10 of the 12 planned sessions will be considered adequate adherence.

Clinical assessments will be conducted at baseline, at the end of treatment in week 6, and at the long-term follow-up in week 30.

The primary endpoint will be the between-group difference in the change from baseline to week 6 in the average number of total daily incontinence episodes, including both SUI and UUI episodes, as recorded in a three-day bladder diary.

Secondary clinical outcomes will include changes in the frequency of SUI and UUI episodes, daytime voiding frequency, nocturia, daily pad use, and urinary-incontinence-related quality of life assessed using the ICIQ-UI SF. Patient-perceived improvement will be assessed using the PGI-I questionnaire, and treatment response will be defined as at least a 50% reduction in the total number of daily incontinence episodes at week 6. Maintenance of treatment effects will be evaluated at week 30.

Urodynamic assessments will be performed at baseline and at week 30 to explore potential treatment-related physiological changes. These assessments will include free uroflowmetry, pressure-flow studies, post-void residual urine volume, the presence of detrusor overactivity, maximum cystometric capacity, evidence of urodynamic stress incontinence, maximum urinary flow rate, and detrusor pressure at maximum flow.

Safety will be evaluated through systematic recording of adverse events during treatment and throughout follow-up.

The primary analysis will follow the intention-to-treat principle.

Inclusion criteria

• Women ≥ 18 years of age.
• Diagnosis of mixed urinary incontinence according to the operational definition.
• Symptom duration ≥ 3 months.
• Minimum severity: ≥ 2 total incontinence episodes documented in the baseline 3-day bladder diary up to 5 incontinence episodes
• Treatment-naive:

• With no pharmacologic treatment for OAB/UI in the previous 8 weeks.
• With no supervised pelvic floor rehabilitation, electrical stimulation, PTNS, neuromodulation, or prior electromagnetic chair therapy (preferably never, for population homogeneity).
• Ability to complete bladder diaries and questionnaires and attend scheduled visits (and all 12 treatment sessions).
• Signed informed consent.

Exclusion criteria

• Active or suspected unresolved urinary tract infection (urinalysis ± culture according to local practice; first episode).
• Uninvestigated macroscopic hematuria.
• Advanced pelvic organ prolapse (POP-Q stage III-IV).
• Pregnancy or postpartum < 2 months.
• Major neurological disease affecting bladder or urethral function.