PreDiabetesPhase 2NCT06526494
Metformin and Vascular Function in Prediabetes
A Phase 2 study testing Metformin in people with PreDiabetes, run by Diana Jalal at 2 sites in United States.
Trial summary
The goal of this clinical trial is to investigate whether metformin improves vascular function in individuals with prediabetes. The main questions it aims to answer are: 1. Does metformin improve large conduit artery endothelial function in individuals with prediabetes? 2. Read more about this study
- Who is it for?
- Ages 18 to 55 years
- Conditions the study is for
- PreDiabetes
- What is being tested?
- Metformin
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 0 participants
- Where
- 2 sitesUnited States
- Study dates
- 13 Nov 2024to 1 Dec 2025
- Phase
- Phase 2
- Are there results?
- None posted in the registry
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 to 55 years
- All sexes
- No healthy volunteers
- Adult
Who may be able to join
- Age 18-55 years
- Prediabetes defined as an HbA1c between 5.7% and 6.4%
- Able to provide informed consent
Who cannot join
- Current use of metformin or metformin use within the past 12 months
- Current use of medicated contraindicated for use with metformin
- Current use of vitamin C supplement
- Current smoker or quit smoking within the last 6 months
- Pregnant, breastfeeding, planning to become pregnant, or unwilling to use adequate birth control
- Uncontrolled hypertension (Systolic blood pressure >140 mmHg)
Show all 15Show fewer
- Body Mass Index > 40 kg/m2
- History of diabetes, myocardial infarction, heart failure, liver disease, or chronic kidney disease (estimated glomerular filtration rate < 45 ml/min/1.73m2)
- History of lactic acidosis
- History of alcohol abuse
- Severe infection within the last 30 days
- Immunosuppressive therapy within the past year
- Life expectancy < 1 year
- Allergy to metformin, nitroglycerin, sodium nitroprusside, ringer's lactate
- Study compliance: Unwilling to fast overnight, have an intravenous catheter placed, take a study drug for 12 weeks, or visit Iowa campus 6 times within a 12-16 week period
Trial locations and contacts
2 sites in 1 country.
United States2 sites
University of Iowa
Iowa City, Iowa, 52242
University of Iowa Hospitals and Clinics
Iowa City, Iowa, 52245
About this study
The goal of this clinical trial is to investigate whether metformin improves vascular function in individuals with prediabetes. The main questions it aims to answer are:
- Does metformin improve large conduit artery endothelial function in individuals with prediabetes?
- Does metformin improve microvascular endothelial function in individuals with prediabetes?
Read more
Researchers will compare metformin to a placebo to see if metformin improves vascular function in prediabetes.
The trial duration is 12 weeks. Participants will take metformin or a placebo once a day for 2 weeks. After 2 weeks, participants will take metformin or a placebo twice a day for the remaining 10 weeks. There will be a screening visit, two baseline visits, a 4-week safety visit, and two 12-week end-of-study visits. Adherence will be calculated from pill count and adverse events will be quantified via a questionnaire.
Read the detailed description
Prediabetes affects approximately 98 million people in the United States and significantly elevates the risk of cardiovascular disease (CVD) and progression to type-2 diabetes. Endothelial dysfunction, characterized by reduced nitric oxide bioavailability, is a key subclinical risk factor contributing to the increased CVD risk in prediabetes. Additionally, endothelial dysfunction exacerbates insulin resistance and hyperglycemia, further elevating the likelihood of progression to overt diabetes. Thus, targeting endothelial dysfunction in prediabetes presents a strategic opportunity to mitigate the risks of both CVD and overt diabetes.
Hyperglycemia-induced reactive oxygen species (ROS) generation reduces nitric oxide bioavailability, driving endothelial dysfunction in prediabetes. Therefore, interventions that lower hyperglycemia could decrease ROS production, enhance nitric oxide bioavailability, and improve endothelial function in prediabetes. Metformin, a first-line anti-diabetic agent, lowers hyperglycemia by reducing hepatic glucose output and enhancing insulin-mediated glucose uptake. Despite its established vascular benefits in diabetes, the effects of metformin on endothelial function in prediabetes remain unexplored.
This study will enroll 30 individuals in a randomized, double-blind, placebo-controlled clinical trial utilizing innovative methodologies to elucidate the vascular benefits of metformin in prediabetes. Specifically, the investigators will assess 1) large conduit artery endothelial function, and 2) cutaneous microvascular endothelial function in prediabetes. By investigating these mechanisms, the investigators aim to provide critical insights into metformin's potential to reduce CVD risk and prevent the progression to diabetes in individuals with prediabetes.
- Conditions
- PreDiabetes
- Being tested
- Metformin, Placebo
- Keywords
- vascular function, metformin, prediabetes
- Medical subject headings
- Prediabetic State
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
MetforminDrug
Oral ingestion for 12 weeks
PlaceboOther
Oral placebo for 12 weeks
| Study group | Role | What they receive |
|---|---|---|
| Metformin | Experimental | Participants will receive metformin 850 mg PO once a day for 2 weeks. After 2 weeks, participants will receive metformin 1700 mg PO once a day for the remaining 10 weeks. Receives: Drug: Metformin |
| Placebo | Placebo comparator | Patients will receive placebo pill identical in appearance and taste to the supplement Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
Macrovascular endothelial function
Brachial artery flow-mediated dilation
Measured: 12 weeks
Secondary outcomes (1)
Microvascular endothelial function
Cutaneous microvascular dilation
Measured: 12 weeks
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted29 Jul 2024
- Study start13 Nov 2024
- Primary completion1 Dec 2025
- Study completion1 Dec 2025
Why it stopped: No funding
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for PreDiabetesStudies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 0 participants (actual)
Sponsor and investigators
- Lead sponsor
- Diana Jalal
- Sponsor type
- University, hospital or other
- Responsible party
- Sponsor-investigator, Diana Jalal, University of Iowa
- Investigators
- Diana I Jalal, MD, Principal investigator, University of Iowa
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT06526494
- Sponsor's protocol ID
- 202403617
- Status last verified
- Dec 2025
- First submitted
- 24 Jul 2024
- Last updated
- 24 Dec 2025
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No
Study at a glance
From the registry record, last updated by the sponsor on 24 Dec 2025. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Metformin and Vascular Function in Prediabetes
- ClinicalTrials.gov ID
- NCT06526494
- Acronym / sponsor ID
- 202403617
- Conditions
- PreDiabetes
- Keywords
- vascular function, metformin, prediabetes
- Phase
- Phase 2
- Study type
- Interventional
- Recruitment status
- WithdrawnReason stopped: No funding
- Enrolment
- 0 participants (actual)
- Lead sponsor
- Diana JalalUniversity, hospital or other
- Study start
- 13 Nov 2024 (actual)
- Primary completion
- 1 Dec 2025 (actual)
- Study completion
- 1 Dec 2025 (actual)
- First posted
- 29 Jul 2024 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
The goal of this clinical trial is to investigate whether metformin improves vascular function in individuals with prediabetes. The main questions it aims to answer are:
- Does metformin improve large conduit artery endothelial function in individuals with prediabetes?
- Does metformin improve microvascular endothelial function in individuals with prediabetes?
Researchers will compare metformin to a placebo to see if metformin improves vascular function in prediabetes.
The trial duration is 12 weeks. Participants will take metformin or a placebo once a day for 2 weeks. After 2 weeks, participants will take metformin or a placebo twice a day for the remaining 10 weeks. There will be a screening visit, two baseline visits, a 4-week safety visit, and two 12-week end-of-study visits. Adherence will be calculated from pill count and adverse events will be quantified via a questionnaire.
Detailed description
Prediabetes affects approximately 98 million people in the United States and significantly elevates the risk of cardiovascular disease (CVD) and progression to type-2 diabetes. Endothelial dysfunction, characterized by reduced nitric oxide bioavailability, is a key subclinical risk factor contributing to the increased CVD risk in prediabetes. Additionally, endothelial dysfunction exacerbates insulin resistance and hyperglycemia, further elevating the likelihood of progression to overt diabetes. Thus, targeting endothelial dysfunction in prediabetes presents a strategic opportunity to mitigate the risks of both CVD and overt diabetes.
Hyperglycemia-induced reactive oxygen species (ROS) generation reduces nitric oxide bioavailability, driving endothelial dysfunction in prediabetes. Therefore, interventions that lower hyperglycemia could decrease ROS production, enhance nitric oxide bioavailability, and improve endothelial function in prediabetes. Metformin, a first-line anti-diabetic agent, lowers hyperglycemia by reducing hepatic glucose output and enhancing insulin-mediated glucose uptake. Despite its established vascular benefits in diabetes, the effects of metformin on endothelial function in prediabetes remain unexplored.
This study will enroll 30 individuals in a randomized, double-blind, placebo-controlled clinical trial utilizing innovative methodologies to elucidate the vascular benefits of metformin in prediabetes. Specifically, the investigators will assess 1) large conduit artery endothelial function, and 2) cutaneous microvascular endothelial function in prediabetes. By investigating these mechanisms, the investigators aim to provide critical insights into metformin's potential to reduce CVD risk and prevent the progression to diabetes in individuals with prediabetes.
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| Metformin | Experimental | Drug: MetforminParticipants will receive metformin 850 mg PO once a day for 2 weeks. After 2 weeks, participants will receive metformin 1700 mg PO once a day for the remaining 10 weeks. |
| Placebo | Placebo comparator | Other: PlaceboPatients will receive placebo pill identical in appearance and taste to the supplement |
Who may qualify
- Ages
- 18 to 55 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult
Key inclusion criteria (3 listed)
- Age 18-55 years
- Prediabetes defined as an HbA1c between 5.7% and 6.4%
- Able to provide informed consent
Key exclusion criteria (15 listed)
- Current use of metformin or metformin use within the past 12 months
- Current use of medicated contraindicated for use with metformin
- Current use of vitamin C supplement
- Current smoker or quit smoking within the last 6 months
- Pregnant, breastfeeding, planning to become pregnant, or unwilling to use adequate birth control
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| MetforminOral ingestion for 12 weeks | Drug | Metformin |
| PlaceboOral placebo for 12 weeks | Other | Placebo |
Primary outcome
Macrovascular endothelial function
Time frame: 12 weeks
Brachial artery flow-mediated dilation
1 secondary outcome
Microvascular endothelial function
Time frame: 12 weeks
Results and safety
The study was withdrawn before enrolling participants, so there are no results.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 24 Dec 2025.
- Individual participant dataSharing planned: No
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part. This study is not recruiting at the moment.
Diana I Jalal, MD principal investigator
University of Iowa
2 sites in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2 study testing Metformin in people with PreDiabetes, run by Diana Jalal at 2 sites in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 3 inclusion and 15 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: withdrawn, as of the sponsor's last update on 24 Dec 2025. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 2 sites in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
The study was withdrawn before enrolling participants, so there are no results.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Macrovascular endothelial function (time frame: 12 weeks). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 24 Dec 2025.