Cranberry Proanthocyanidins and Lactobacilli for Recurrent UTI Prevention in Type 2 Diabetes

September 16, 2026 updated by: National Institute of Endocrinology, Georgia

High-Potency Cranberry Proanthocyanidins and Lactobacilli for Recurrent Urinary Tract Infection Prevention in Women With Type 2 Diabetes: A Prospective Single-Arm Feasibility Study

The purpose of this prospective, single-arm feasibility study was to evaluate the operational feasibility, tolerability, safety, and exploratory clinical outcomes of an oral supplement combining standardized cranberry proanthocyanidins (PACs) and a multi-strain Lactobacillus formulation in women with type 2 diabetes mellitus and a documented history of recurrent urinary tract infections (rUTIs).

Participants received a 60-day active intervention consisting of a combined capsule taken twice daily, followed by a 120-day observation period without study intervention, for a total follow-up duration of 180 days. Primary feasibility outcomes included screening and enrollment metrics, retention rate at day 180, and tolerability/adverse event rates. Exploratory endpoints included the incidence of microbiologically confirmed symptomatic UTIs and changes in antibiotic prescription rates compared with pre-enrollment history.

Study Overview

Status

Completed

Conditions

Intervention / Treatment

Detailed Description

Women with type 2 diabetes mellitus (T2DM) are disproportionately affected by recurrent urinary tract infections due to glucosuria, impaired innate immune defenses, and urogenital dysbiosis, which is often compounded by the use of sodium-glucose cotransporter-2 (SGLT2) inhibitors.

This prospective, open-label, single-arm feasibility study was conducted at the National Institute of Endocrinology in Tbilisi, Georgia. Eligible participants were women aged 40 to 75 years with established T2DM (HbA1c 6.5%-10.0%) and a confirmed history of recurrent UTIs (defined as >=2 episodes in the prior 12 months or >=1 in the prior 6 months) without active infection at enrollment.

The study protocol comprised:

  1. Screening window: up to 14 days to confirm eligibility and baseline stability.
  2. Active intervention phase: 60 consecutive days of oral supplementation with a commercial capsule containing 72 mg of standardized cranberry PACs and 2x10^9 CFU of a multi-strain Lactobacillus formulation (L. rhamnosus, L. acidophilus, L. casei) taken twice daily with meals (total 144 mg PACs daily).
  3. Observation phase: 120 days of prospective follow-up without study supplementation.

Standard glucose-lowering therapies (including metformin and SGLT2 inhibitors) were maintained unchanged throughout the 180-day study. The study was designed to generate operational, safety, and preliminary signal data to inform the sample size calculation and methodological design of a future randomized, double-blind, placebo-controlled clinical trial.

Study Type

Interventional

Enrollment (Actual)

100

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 Locations

  • Georgia
      • Tbilisi, Georgia, 0159
        • National Institute of Endocrinology

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

40 years to 75 years (Adult, Older Adult)

Accepts Healthy Volunteers

No

Genders Eligible for Study

Female

Description

Inclusion Criteria:

  1. Female patients aged 40 to 75 years.
  2. Established diagnosis of type 2 diabetes mellitus for >= 12 months.
  3. Baseline glycated hemoglobin (HbA1c) between 6.5% and 10.0%.
  4. Documented history of recurrent urinary tract infections (>= 2 episodes in the preceding 12 months or >= 1 episode in the preceding 6 months).
  5. Absence of active symptomatic UTI at enrollment, verified by screening urine analysis and culture.
  6. Maintained on stable glucose-lowering therapy for at least 3 months prior to enrollment.
  7. Willing and able to comply with the 60-day supplementation and 180-day follow-up protocol.
  8. Provided written informed consent.

Exclusion Criteria:

  1. Active, symptomatic urinary tract infection at the time of screening.
  2. Known anatomical or functional urinary tract abnormalities (e.g., neurogenic bladder, urinary tract obstruction, indwelling catheter).
  3. Severe renal impairment (eGFR < 30 mL/min/1.73 m2) or end-stage renal disease.
  4. Severe hepatic impairment or active malignancy.
  5. Routine use of systemic antibiotic prophylaxis for UTI within 30 days prior to screening.
  6. Regular intake of cranberry-containing supplements, D-mannose, or commercial probiotic formulations within 30 days prior to enrollment.
  7. Known allergy or hypersensitivity to cranberry extracts, proanthocyanidins, or any excipient in the study formulation.
  8. Pregnancy, lactation, or women planning pregnancy during the study duration.

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: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: Active Supplementation Arm

Participants received oral capsules containing standardized cranberry proanthocyanidins (72 mg) and multi-strain Lactobacillus (2x10^9 CFU) twice daily for 60 consecutive days, followed by a 120-day observation phase.
Dietary supplement: Cranberry Proanthocyanidins and Lactobacilli

Oral capsule containing 72 mg of standardized cranberry proanthocyanidins (PACs) and 2x10^9 CFU multi-strain Lactobacillus (L. rhamnosus, L. acidophilus, L. casei), administered twice daily with meals for 60 consecutive days.

Other Names:
  • Cranberry PACs + Probiotic formulation

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Study Completion and Retention Rate
Time Frame: Day 180

Proportion of enrolled participants who successfully completed the entire 180-day protocol (comprising the 60-day active supplementation phase and the 120-day observation phase) without premature discontinuation.
Day 180

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Incidence of Symptomatic Recurrent Urinary Tract Infections (rUTIs)
Time Frame: Day 1 to Day 180

Number of microbiologically confirmed symptomatic UTI episodes (presence of acute urinary symptoms accompanied by significant bacteriuria >= 10^3 to 10^5 CFU/mL) recorded per participant during the 180-day evaluation period.
Day 1 to Day 180
Frequency of Antibiotic Courses Prescribed for UTI
Time Frame: Day 1 to Day 180

Total number of systemic antibacterial treatment courses initiated for acute symptomatic urinary tract infections during the 180-day study period.
Day 1 to Day 180
Incidence of Treatment-Emergent Adverse Events
Time Frame: Day 1 to Day 60 (active intervention period)

Incidence, severity, and causality assessment of adverse events reported during the active supplement period, with particular focus on gastrointestinal tolerability (e.g., dyspepsia, nausea, abdominal discomfort).
Day 1 to Day 60 (active intervention period)

Collaborators and Investigators

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

Sponsor

National Institute of Endocrinology, Georgia

Investigators

  • Principal Investigator: Shota Janjgava, MD, PhD, National Institute of Endocrinology, Georgia

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)

September 10, 2025

Primary Completion (Actual)

March 18, 2026

Study Completion (Actual)

March 18, 2026

Study Registration Dates

First Submitted

September 16, 2026

First Submitted That Met QC Criteria

September 16, 2026

First Posted (Actual)

September 22, 2026

Study Record Updates

Last Update Posted (Actual)

September 22, 2026

Last Update Submitted That Met QC Criteria

September 16, 2026

Last Verified

September 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • NIE-T2D-UTI-01

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-identified individual participant data that underlie the results reported in this article will be made available upon reasonable request to qualified academic researchers for scientific verification.

IPD Sharing Time Frame

Data will be available beginning 6 months and ending 36 months following publication of the study results.

IPD Sharing Access Criteria

De-identified individual participant data will be made available to qualified academic researchers upon reasonable request with a methodologically sound proposal. Requests should be directed to the study investigators and are subject to institutional data-sharing approval.

IPD Sharing Supporting Information Type

  • STUDY_PROTOCOL
  • ICF

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

No

Studies a U.S. FDA-regulated device product

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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