A Trial of D-mannose for the Prophylaxis of Recurrent Urinary Tract Infections (DmannoseRCT)

September 18, 2025 updated by: Philippe Zimmern, University of Texas Southwestern Medical Center

A Randomized Controlled Trial of D-mannose for the Prophylaxis of Recurrent Urinary Tract Infections in Post-menopausal Women

A randomized, double-blind, placebo-controlled, 12-month study to determine the effectiveness of D-mannose (2g daily) supplementation in rUTI (recurrent urinary tract infection) prevention in post-menopausal women.

Study Overview

Status

Recruiting

Conditions

Intervention / Treatment

Detailed Description

The proposed study on D-mannose prophylaxis is designed to address a critical unmet medical need to improve the understanding and prevention of rUTI (recurrent urinary tract infection) in post-menopausal women, a population disproportionately affected by rUTI and understudied. The efficacy of D-mannose on preventing uncomplicated rUTI will be elucidated, and additional study measures (including urine culture and one-hour D-mannose test results) may help establish an ideal candidate for responding to daily D-mannose intake over time. The proposed study will follow CONSORT guidelines for randomized clinical trial studies.

Aim 1. Test the hypothesis that D-mannose provides effective rUTI prophylaxis in post-menopausal women over 6 months.

Aim 2. Test the hypothesis that D-mannose provides effective rUTI prophylaxis in post-menopausal women beyond 6 months and up to one year.

The overarching hypotheses are that (1) D-mannose will be found superior to placebo in preventing rUTI in post-menopausal women over 6 months as suggested by one prior RCT7 (Aim 1) and (2) D-mannose will remain effective for rUTI prophylaxis up to one year (Aim 2).

Ninety (90) women currently UTI-free and with a history of uncomplicated rUTI, defined as ≥ 2 symptomatic UTIs in 6 months or ≥ 3 symptomatic UTIs in 12 months, will be enrolled and randomized (2:1 ratio) to receive D-mannose (2g, i.e., 4 x 500mg capsules) or placebo daily for 12 months.

Study Type

Interventional

Enrollment (Estimated)

90

Phase

  • Not Applicable

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Contact

Study Contact Backup

Study Locations

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

  • Adult
  • Older Adult

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • Female, post-menopausal, age ≥ 55 years old
  • Diagnosis of recurrent UTI, defined as ≥ 3 symptomatic culture-proven UTI episodes in 12 months or ≥ 2 in 6 months.
  • Currently free from a UTI determined based on absence of symptoms as determined by the UTI symptom assessment questionnaire79 and negative urine culture (<103 colony forming units per ml of urine).
  • Able to attend all follow-up appointments for the study.
  • A negative upper and lower urinary tract evaluation, including pelvic examination for pelvic organ prolapse (less than stage 2), measurement of post-void residual (less than 50 ml), and imaging (renal ultrasound and standing voiding cystourethrogram) to exclude kidney stone, hydronephrosis, reflux, or urethral diverticulum.

Exclusion Criteria:

  • Current use of D-mannose. Patients willing to stop taking D-mannose will be offered to join the trial after a 4-week wash-out period.
  • Complicated UTIs, including need for catheter drainage or intermittent catheterization, neurogenic bladder, bladder augmentation, or urinary diversion.
  • Ongoing supplement use (Box 1). Patients willing to stop taking the listed supplements will be offered to join the trial after a 4-week wash-out period.
  • Evidence of upper tract infection (pyelonephritis), including temperature higher than 38°C, flank/lumbar pain or tenderness
  • Diagnosis of interstitial cystitis or overactive bladder syndrome
  • Prophylactic antibiotics started in the last 3 months and unwilling to discontinue, or intention to start in the next 12 months
  • Use of Uromune or other vaccine approaches to reduce rUTI
  • Participation in a research study involving an investigational product in the past 12 weeks
  • Receipt of phage treatment
  • History of chronic diarrhea requiring regular therapy
  • Inability to swallow or known history of gastrointestinal malabsorption
  • History of recurrent vaginal yeast infections
  • Systemic disease precluding enrollment in this study (uncontrolled diabetes with HgA1C above 7, ongoing chemotherapy or immunotherapy, renal insufficiency [creatinine > 1.5 g/dl]), mental or cognitive impairment, weight loss diet requiring excessively large amounts of fluid intake, or other health-related specific diet).
  • Nursing home resident
  • BMI >40

Box 1 Supplements to avoid

  • Multi-Vitamins and Multi-Mineral capsules
  • Specific Vitamins or Minerals (e.g., Calcium, Citrical, Calcium Gummies, Vitamin A, D, Niacin, Pyridoxine, Selenium, Vitamin E, B6, Iron, Omega 3, D3, Magnesium, B-Complex, Women's Ultra MultiVitamin, GNC B-Complex, B-12, PreserVision Areds2, Vitamins D, B Pollen)
  • Probiotics
  • Cranberry Mannose or Cranberry Extract Weight loss products to avoid
  • Medifast
  • Vitafusion
  • OptiVin Products
  • Appetite Suppressants
  • Keto-Fuel

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Prevention
  • Allocation: Randomized
  • Interventional Model: Parallel Assignment
  • Masking: Quadruple

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Placebo Comparator: Placebo
Dietary Supplement: Placebo
Dietary supplement: Placebo
Placebo daily for 12 months.
Active Comparator: D-mannose
Dietary Supplement: D-Mannose
Dietary supplement: D-Mannose
D-mannose (2g, i.e., 4 x 500mg capsules) daily for 12 months.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Failure rate
Time Frame: Through study completion, an average of 5 years
To determine whether prophylaxis with D-mannose reduces the incidence of UTI episodes compared to placebo. "Failure rate," defined as having 2 UTIs in 6 months or 3 in one year.
Through study completion, an average of 5 years

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Number of UTI antibiotic treatments
Time Frame: Through study completion, an average of 5 years

To investigate if D-mannose reduces the need for antibiotic use due to recurrent UTIs (measured as number of antibiotic courses for symptomatic culture-proven UTI episodes) compared to placebo.

Number of UTI antibiotic treatments during the 6 months of treatment. If the participant receives >1 antibiotic course for UTI without symptom relief, it is regarded as one episode and counted as one antibiotic treatment. If there has been an asymptomatic period of at least 14 days in between two UTI antibiotic courses, this will be regarded as a new antibiotic treatment.
Through study completion, an average of 5 years
Symptom severity
Time Frame: Through study completion, an average of 5 years
To investigate if D-mannose reduces the severity of UTI symptoms compared to placebo. Record symptom severity using a validated UTI symptom assessment questionnaire.
Through study completion, an average of 5 years
Serious adverse events associated with D-mannose
Time Frame: Through study completion, an average of 5 years
To determine the frequency of serious adverse events associated with D-mannose. Number of participants who experienced adverse events >= Grade 3, as defined by Common Terminology Criteria for Adverse Events by CTCA version 5.0.
Through study completion, an average of 5 years

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

University of Texas Southwestern Medical Center

Investigators

  • Principal Investigator: Philippe Zimmern, MD, University of Texas Southwestern Medical Center

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

August 1, 2025

Primary Completion (Estimated)

September 30, 2029

Study Completion (Estimated)

September 30, 2030

Study Registration Dates

First Submitted

April 11, 2025

First Submitted That Met QC Criteria

April 15, 2025

First Posted (Actual)

April 23, 2025

Study Record Updates

Last Update Posted (Actual)

September 22, 2025

Last Update Submitted That Met QC Criteria

September 18, 2025

Last Verified

September 1, 2025

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • STU-2024-1090

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

NO

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

No

product manufactured in and exported from the U.S.

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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