Background/significance: Overactive Bladder Syndrome (OAB) is defined as urinary urgency,
with or without urgency incontinence, and usually accompanied by frequency and nocturia.
OAB remains an increasingly more prevalent disease, affecting over 45% of postmenopausal
women over the age 65 within the United States. Epidemiological research continues to
consistently highlight OAB's impact on patience's mental health, sleep quality, physical
activity, occupational productivity and overall quality of life. OAB's economic burden
cannot be overstated as well as a US cost-of-illness study reported a total cost of $66
billion in 2007 and estimated cost of over $82 billion in 2021.
Mainstay first-line forms of management for OAB include behavioral modifications such as
bladder training (timed voiding, urge suppression techniques), pelvic floor physical
therapy, fluid management and bladder irritant restrictions. Second-line forms of
management consistent of pharmacotherapy including oral anticholinergics or beta-3
adrenoreceptor agonists. Multiple studies have shown that vaginal estrogen improves
symptoms of urinary urgency and frequency in postmenopausal women. Limited data currently
exist comparing beta-3 antagonists to vaginal estrogen use for overactive bladder
syndrome as well as the combination of both.
Purpose: This study aims to compare the efficacy of vaginal estradiol with that of oral
mirabegron in the treatment of overactive bladder in postmenopausal women and
characterize outcomes in women undergoing combined therapy.
Study design: This is a single site, double-blinded, randomized controlled trial for 152
postmenopausal women with urinary frequency, urgency, nocturia with or without urgency
urinary incontinence symptoms. Patient's will be randomized between 0.01% vaginal
estradiol cream 1/2 gram once nightly for two weeks then three times per week or 50
milligrams oral Mirabegron once a night.
Procedures: Postmenopausal women with bothersome OAB symptoms will be eligible for the
study. OAB symptoms will be based on the OAB-q (SF) symptom bother questionnaire with an
initial score greater than 20. Other inclusion criteria include ability to speak English.
Exclusion criteria include: Post void residual >200mL or >1/3 patient's total bladder
volume, currently on or previously taking anticholinergic or beta- 3 antagonists within
the past 1 month, untreated, symptomatic pelvic organ prolapse greater than Stage 2,
contraindication to vaginal estrogen therapy, contraindication to Mirabegron, undiagnosed
postmenopausal vaginal bleeding within the past 12 months, current diagnosis of a
condition which explains their overactive bladder or incontinence symptoms.
Participants who elect to enroll will have a post-void residual determined, a demographic
sheet, the OAB-q (SF) health-related quality of life (HRQL) questionnaire, a 24-hour
voiding diary and Patient Global Impression of Severity (PGI-S). Participants will be
randomized via random allocation rule fixed blocking in a 1:1 ratio to either vaginal
estrogen or oral Mirabegron. After 12 weeks of single therapy, the patients will be
contacted for follow up to complete all previous questionnaires, a 24-hour voiding diary
as well as the PGI-I questionnaire. After the initial 12-weeks, single therapy follow up
appointment, participants will be offered dual treatment (both vaginal estrogen and
Mirabegron same doses/frequencies.) If the patient agrees she will receive dual treatment
for 12 weeks and follow up with the same questionnaires.