NCT02915198 · VA Office of Research and Development
Investigation of Metformin in Pre-Diabetes on Atherosclerotic Cardiovascular OuTcomes
(VA-IMPACT)
What this study is about
This research will help us to learn if the medicine called metformin reduces the risk of death, heart attacks, and/or strokes in Veterans who have pre-diabetes and heart or blood vessel problems.
View original scientific description
This research will help us to learn if the medicine called metformin reduces the risk of death, heart attacks, and/or strokes in Veterans who have pre-diabetes and heart or blood vessel problems.
Interventions
DRUG
Metformin XR
The study medication dose may be increased by a step-wise fashion up to a maximum of 4 tablets per day.
DRUG
Placebo
For patients \< 80 years of age at the time of a study visit, and with most recent eGFR 45 mL/min/1.73 m2, study medication dose may be increased in a stepwise fashion to a maximum of 4 tablets daily, corresponding to metformin XR 2000 mg or matching placebo. For patients 80 years of age or with most recent 30 eGFR \< 45 mL/min/1.73 m2, the maximum dose of study medication is 2 tablets daily, corresponding to metformin XR 1000 mg or matching placebo
Primary outcome measures
Time in days to death, non-fatal myocardial infarction, stroke, hospitalization for unstable angina, or symptom-driven coronary revascularization
Time frame: through study completion, an average of 4.5 years
The primary outcome measure is the time to first occurrence of death, non-fatal myocardial infarction or stroke, hospitalization for unstable angina with objective evidence of acute myocardial ischemia, or coronary revascularization driven by acute or progressive symptoms.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- 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 criteri
Where
- Phoenix, Arizona
- Tucson, Arizona
- Little Rock, Arkansas
- Loma Linda, California
- Long Beach, California
- Palo Alto, California
- San Diego, California
- West Los Angeles, California
- Aurora, Colorado
- West Haven, Connecticut
- Bay Pines, Florida
- Gainesville, Florida
And 28 more locations — see the full list below.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Dec 17, 2025 · Source of record for eligibility and locations