Clinical trial Recruiting at 37 sites Phase 4 Interventional Ages 18 and up

Using Metformin to Reduce Heart Risks in Veterans with Prediabetes

Official title: CSP #2002 - Investigation of Metformin in Pre-Diabetes on Atherosclerotic Cardiovascular OuTcomes (VA-IMPACT)

Run by VA Office of Research and Development · NCT02915198 · Data updated 2026-11-12

This study tests if the diabetes drug metformin can help reduce the risk of heart attacks, strokes, and death in Veterans with prediabetes and heart disease.

Quick facts

PhasePhase 4
Study typeInterventional
Ages18 Years and up
SexAll
Enrollment7410 (estimated)
SponsorVA Office of Research and Development
Federal
Locations40 sites (Phoenix, Arizona and 39 other locations)
StatusRecruiting
StartedApril 3, 2023
Main results expectedSeptember 28, 2029
Study endsSeptember 28, 2029
Registry record updatedDecember 17, 2025
Trial IDNCT02915198 on ClinicalTrials.gov

Is this trial a fit for you?

Likely a good fit

Ideal candidates are Veterans with pre-diabetes and established atherosclerotic cardiovascular disease.

Probably not a fit

Patients without pre-diabetes or those without established cardiovascular disease may not benefit from this study.

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This clinical trial investigates whether metformin can lower the risk of death, heart attacks, and strokes in Veterans diagnosed with pre-diabetes and existing atherosclerotic cardiovascular disease. It is a multicenter, randomized, double-blind trial where participants are assigned to receive either metformin or a placebo. Eligible patients must meet specific criteria for pre-diabetes and have established cardiovascular disease. The study aims to provide insights into the effectiveness of metformin in improving cardiovascular outcomes in this high-risk population.

Why it matters

Potential benefit: If successful, this study could significantly reduce cardiovascular events and mortality in Veterans with pre-diabetes.

How similar studies have gone: Previous studies have shown promising results for metformin in similar populations, suggesting potential for success in this trial.

Who can join: the full rules

Show full inclusion / exclusion criteria
Inclusion Criteria:

1. Pre-diabetes: This condition is fulfilled by HbA1c of at least 5.7%, but less than 6.5%; or two measurements of fasting plasma glucose (on separate days) of 100-125 mg/dL; or a 2-hour plasma glucose level of 140-199 mg/dL following a 75 g glucose load oral glucose tolerance test.
2. Established atherosclerotic cardiovascular disease: Qualifying participants must have evidence of atherosclerotic disease in at least one of the following vascular beds: coronary, cerebrovascular, or peripheral arterial circulation.

Coronary artery disease is fulfilled by at least one of (1), (2), or (3):

1. History of myocardial infarction at least one month prior to randomization.
2. History of percutaneous coronary intervention or coronary artery bypass surgery at least one month prior to randomization.
3. Angiographic evidence of coronary stenosis of at least 50% in at least two major epicardial coronary arteries.

Cerebrovascular disease is fulfilled by at least one of criteria (1) through (4):

1. Documented prior ischemic stroke (at least one month prior to randomization),
2. Carotid artery stenosis 50% and history of transient ischemic attack or transient ischemic visual symptoms attributable to the identified lesion(s),
3. Asymptomatic carotid stenosis of at least 70% luminal diameter,
4. History of carotid revascularization (surgical or catheter-based).

Peripheral arterial disease: Fulfilled by at least one of the following:

1. History of aorto-iliac or peripheral artery intervention (surgical or catheter based) for limb ischemia, or amputation for limb ischemia,
2. Symptoms of intermittent claudication with ankle:brachial index less than or equal to 0.85.

3\. Renal function: Estimated glomerular filtration rate at least 45 mL/min/1.73 m2.

4\. Informed consent has been fully executed, and participant agrees to study procedures.

Exclusion Criteria:

1. Treatment with metformin or other anti-diabetic medication within 12 months of randomization. Note: In the absence of a diagnosis of diabetes, inpatient treatment with insulin or treatment with an SGLT2 inhibitor (e.g., for heart failure) or a GLP-1 receptor agonist (e.g., for obesity) is not exclusionary.
2. Treatment with systemic glucocorticoids within 3 months of randomization
3. Fasting plasma glucose greater than 130 mg/dL measured between screening and randomization visits, or any plasma glucose 180 mg/dL or HbA1c 7.0% measured within 12 months of randomization.
4. Total CO2 below the local laboratory lower limit of normal on most recent blood chemistry panel
5. Current treatment with cimetidine, vandetanib, or a systemic treatment with a carbonic anhydrase inhibitor.
6. Cirrhosis, active hepatitis, or jaundice at time of randomization, or total bilirubin \> 2 times upper limit of normal
7. Binge or heavy alcohol consumption within 6 months of randomization
8. Severe anemia (hemoglobin \< 10 g/dL)
9. Prior history of intolerance to metformin
10. Myocardial infarction, coronary revascularization procedure, or stroke within 1 month of randomization
11. Uncontrolled hypertension at screening assessment (systolic blood pressure 180 mm Hg or diastolic blood pressure 110 mm Hg
12. Acute or decompensated congestive heart failure
13. Expected survival less than study duration
14. Participants considered to be unable, unwilling, or unreliable to meet protocol requirements
15. Impaired decision-making capacity, defined by any history of dementia or cognitive impairment
16. Concurrent participation in another research study involving a randomized comparison of drug or device treatments, unless specifically excepted.
17. Pregnant, intent to become pregnant during the trial, or lactating
18. Women of childbearing potential who are not using a highly effective method of contraception

Where it's running

  • Phoenix VA Health Care System, Phoenix, AZ
    Phoenix, Arizona, United States
    Recruiting
  • Southern Arizona VA Health Care System, Tucson, AZ
    Tucson, Arizona, United States
    Recruiting
  • Central Arkansas VHS John L. McClellan Memorial Veterans Hospital, Little Rock, AR
    Little Rock, Arkansas, United States
    Recruiting
  • VA Loma Linda Healthcare System, Loma Linda, CA
    Loma Linda, California, United States
    Recruiting
  • VA Long Beach Healthcare System, Long Beach, CA
    Long Beach, California, United States
    Recruiting
  • VA Palo Alto Health Care System, Palo Alto, CA
    Palo Alto, California, United States
    Recruiting
Show 34 more locations
  • VA San Diego Healthcare System, San Diego, CA
    San Diego, California, United States
    Recruiting
  • VA Greater Los Angeles Healthcare System, West Los Angeles, CA
    West Los Angeles, California, United States
    Recruiting
  • Rocky Mountain Regional VA Medical Center, Aurora, CO
    Aurora, Colorado, United States
    Recruiting
  • VA Connecticut Healthcare System West Haven Campus, West Haven, CT
    West Haven, Connecticut, United States
    Recruiting
  • Bay Pines VA Healthcare System, Pay Pines, FL
    Bay Pines, Florida, United States
    Recruiting
  • North Florida/South Georgia Veterans Health System, Gainesville, FL
    Gainesville, Florida, United States
    Recruiting
  • Miami VA Healthcare System, Miami, FL
    Miami, Florida, United States
    Recruiting
  • Atlanta VA Medical and Rehab Center, Decatur, GA
    Decatur, Georgia, United States
    Recruiting
  • VA Pacific Islands Health Care System, Honolulu, HI
    Honolulu, Hawaii, United States
    Recruiting
  • Edward Hines Jr. VA Hospital, Hines, IL
    Hines, Illinois, United States
    Recruiting
  • Iowa City VA Health Care System, Iowa City, IA
    Iowa City, Iowa, United States
    Recruiting
  • Rehabilitation R&D Service, Baltimore, MD
    Baltimore, Maryland, United States
    Recruiting
  • VA Boston Healthcare System Jamaica Plain Campus, Jamaica Plain, MA
    Boston, Massachusetts, United States
    Recruiting
  • Minneapolis VA Health Care System, Minneapolis, MN
    Minneapolis, Minnesota, United States
    Recruiting
  • Kansas City VA Medical Center, Kansas City, MO
    Kansas City, Missouri, United States
    Recruiting
  • Omaha VA Nebraska-Western Iowa Health Care System, Omaha, NE
    Omaha, Nebraska, United States
    Recruiting
  • New Mexico VA Health Care System, Albuquerque, NM
    Albuquerque, New Mexico, United States
    Recruiting
  • Manhattan Campus of the VA NY Harbor Healthcare System, New York, NY
    New York, New York, United States
    Recruiting
  • Durham VA Medical Center, Durham, NC
    Durham, North Carolina, United States
    Recruiting
  • Louis Stokes VA Medical Center, Cleveland, OH
    Cleveland, Ohio, United States
    Recruiting
  • VA Portland Health Care System, Portland, OR
    Portland, Oregon, United States
    Recruiting
  • Ralph H. Johnson VA Medical Center, Charleston, SC
    Charleston, South Carolina, United States
    Recruiting
  • Wm. Jennings Bryan Dorn VA Medical Center, Columbia, SC
    Columbia, South Carolina, United States
    Recruiting
  • Memphis VA Medical Center, Memphis, TN
    Memphis, Tennessee, United States
    Recruiting
  • VA North Texas Health Care System Dallas VA Medical Center, Dallas, TX
    Dallas, Texas, United States
    Recruiting
  • Michael E. DeBakey VA Medical Center, Houston, TX
    Houston, Texas, United States
    Recruiting
  • VA Salt Lake City Health Care System, Salt Lake City, UT
    Salt Lake City, Utah, United States
    Recruiting
  • Hunter Holmes McGuire VA Medical Center, Richmond, VA
    Richmond, Virginia, United States
    Recruiting
  • Salem VA Medical Center, Salem, VA
    Salem, Virginia, United States
    Recruiting
  • Huntington VA Medical Center, Huntington, WV
    Huntington, West Virginia, United States
    Recruiting
  • Clement J. Zablocki VA Medical Center, Milwaukee, WI
    Milwaukee, Wisconsin, United States
    Recruiting
  • Jesse Brown VA Medical Center, Chicago, IL
    Chicago, Illinois, United States
    Terminated
  • Lexington VA Medical Center, Lexington, KY
    Lexington, Kentucky, United States
    Not yet recruiting
  • Cincinnati VA Medical Center, Cincinnati, OH
    Cincinnati, Ohio, United States
    Active not recruiting

Study contacts

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

How to take part

  1. Review the eligibility criteria above with your treating physician.
  2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
  3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.
Last reviewed 2026-11-14 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.