Project Summary

What is the research about?

Urgency urinary incontinence is a common, bothersome condition of losing control of urine, associated with a feeling of urgency. The condition is especially common among older women, and causes a large burden of shame, discomfort, falls, expense, and even nursing home admission. The condition is also associated with an increased risk of death. Urgency incontinence has several effective treatments, but most of them are not well suited to for use among older women. For instance, anticholinergic medications, long relied upon as the standard treatment, are no longer recommended in older patients, due to evidence of a 65% increased risk of dementia associated with chronic use.

By contrast, onabotulinumtoxinA (BTX, trade name BOTOX©) shows promise as a treatment for older women. Studies have shown that when injected into the bladder wall, BTX is effective, safe, and cost effective. BTX treatment is an office-based procedure that can produce symptom relief for 6 months or longer. So far, however, research studies about use of BTX have focused on younger women. The available evidence among older women is mixed, with some studies suggesting shorter length of benefit from the BTX treatment compared with younger women, or longer lasting side effects (i.e., difficulty emptying the bladder).

The goal of this study is to learn more about the effectiveness and side effects of BTX injection specifically among older women, and to compare two doses of the medication: i) the standard dosage that has been extensively studied among younger women; and ii) a lower dosage that has been shown to be effective, and might have lower side effects like difficulty emptying the bladder. We are also interested in learning more about the factors that may make one woman experience greater benefit from BTX treatment, compared with another woman.

Who can this research help?

Older women with urgency incontinence, their caregivers, medical providers who care for them, and policymakers who try to improve options for treatment of urgency urinary incontinence for older adults.

What is the research team doing?

The research team is working with six hospitals across the country to enroll 258 women aged 70 and older who have urgency urinary incontinence, despite treatments such as behavioral modification and medications. The team is assigning patients by chance to one of two groups. Each group has an equal number of patients who are frail or non-frail (as determined by a standardized assessment). Patients in one group will receive standard-dose treatment with injection of onabotulinumtoxinA in the bladder. Patients in the second group will receive lower-dose treatment with injection of the same medication. Over 12 months, the team will compare changes in the patients’ quality of life, severity of and distress caused by symptoms, signs/symptoms of depression, satisfaction with treatment, out of pocket costs, side effects like difficulty emptying the bladder normally, and experience of the treatment.

To design and conduct this study, the research team is working with patients, caregivers, and healthcare providers, as well as representatives from patient advocacy, provider and social support organizations, and industry.

Research methods at a glance

Design: Randomized controlled trial using mixed methods

Population: Spanish- and English-speaking women aged 70 years and older with urgency urinary incontinence not responsive to initial therapies


  • Low-dose (50 unit) bladder BTX injection
  • Standard-dose (100 unit) bladder BTX injection


  • Primary: Quality of life related to incontinence symptoms
  • Secondary: Symptom severity and distress, Incontinence frequency, Patient satisfaction, Global symptom improvement, Attainment of patient goals for treatment, General health-related quality of life, Procedural discomfort and adverse events including urinary retention & duration, Qualitative patient experience, Third-party payor costs and Patient out-of-pocket costs

Timeframe: 12-month follow-up for primary outcome, with primary endpoint of 3 months after BTX treatment

Project Information

Anne Cooper, MD, MA
Elizabeth Gormley, MD
Dartmouth-Hitchcock Clinic

Key Dates

March 2022
October 2027

Study Registration Information


Award Type
Health Conditions Health Conditions These are the broad terms we use to categorize our funded research studies; specific diseases or conditions are included within the appropriate larger category. Note: not all of our funded projects focus on a single disease or condition; some touch on multiple diseases or conditions, research methods, or broader health system interventions. Such projects won’t be listed by a primary disease/condition and so won’t appear if you use this filter tool to find them. View Glossary
Populations Populations PCORI is interested in research that seeks to better understand how different clinical and health system options work for different people. These populations are frequently studied in our portfolio or identified as being of interest by our stakeholders. View Glossary
Intervention Strategy Intervention Strategies PCORI funds comparative clinical effectiveness research (CER) studies that compare two or more options or approaches to health care, or that compare different ways of delivering or receiving care. View Glossary
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Last updated: October 18, 2023