GLP-1 vs Metformin in Prediabetes: What the AHA Study Shows

What happened / Why it matters

What happened. The American Heart Association (AHA) released a summary on Nov. 2, 2026 of a study that compared GLP-1 drugs with metformin in adults who have prediabetes and obesity. The release says the study is being presented at the AHA Scientific Sessions, held Nov. 6 to 9 in Chicago. People who took GLP-1 drugs had better outcomes than people who took metformin.

Why it matters. The numbers are large, and a headline can make them sound like proof that GLP-1 drugs are better than metformin for preventing diabetes. The study cannot show that. This article covers what the AHA release reports and what it does not. It is not medical advice.

This was an observational study of health records presented as a conference abstract. It has not been published in a peer-reviewed journal and cannot show that GLP-1 drugs caused the differences.

What did the researchers do?

According to the AHA release:

• Records. They reviewed electronic health records of 256,492 adults diagnosed with prediabetes and obesity, from 104 institutions in the TriNetX network, 2010 to 2023. The average age was 52 and 76% were women.
• Comparison. They compared people who took metformin with people who took a GLP-1 medication, looking at blood sugar, progression to type 2 diabetes, heart disease, stroke and death. They followed people for an average of roughly three years.
• Matching. They paired records of patients with similar ages, health conditions (such as high blood pressure, sleep apnea or nicotine dependence) and medications.

What did they find?

Compared with people who took metformin, people who took GLP-1 drugs had, according to the release:

• a 1.5 times higher chance of bringing high blood sugar back to normal levels;
• a 31% lower risk of developing type 2 diabetes; and
• a 41% lower risk of death from any cause, which the release describes over a five-year period.

The release also reports 15% fewer heart attacks, 20% fewer strokes, 25% fewer cases of heart failure and 8% fewer cases of atrial fibrillation with GLP-1 drugs. The 41% figure is for death from any cause. It is not a measure of heart events alone.

Why can’t the study show cause?

People were not randomly assigned to GLP-1 drugs or metformin. Even after matching, the groups may have differed in ways the records don’t capture, such as weight loss, access to care or how consistently they took the medication.

The AHA release lists these limitations:

• The study is observational and cannot prove cause and effect.
• Patients and outcomes were identified through diagnosis codes, which can be incomplete.
• The researchers relied on prescription records, so how consistently patients took the medication, or at what dose, is not reflected.
• GLP-1 medications were grouped together, so differences between individual drugs were not considered.

An American Heart Association past president said the benefits likely reflect weight loss. In the release, Robert Eckel, M.D., who was not involved in the study, said the benefits “likely relates to the patients losing weight, which is known to help prevent Type 2 diabetes.” He also said costs and access to these medications are important factors.

Some details also limit who the findings apply to. Everyone in the study had obesity as well as prediabetes, and three-quarters were women, so the results do not describe people with prediabetes who do not have obesity.

What is the regulatory status?

Neither GLP-1 drugs nor metformin are FDA-approved specifically for prediabetes. Some GLP-1 drugs are approved for weight management in adults with obesity. Examples are Wegovy (semaglutide) and Zepbound (tirzepatide), and their labels have their own safety information. Metformin’s FDA labels list type 2 diabetes as the indication.

What do diabetes guidelines say?

The AHA release describes metformin as “the current gold-standard, first-line medication” for prediabetes and type 2 diabetes, along with lifestyle modification. The diabetes guideline is more specific. For adults with overweight or obesity at high risk of type 2 diabetes, the American Diabetes Association recommends a diabetes prevention program aimed at losing at least 5% to 7% of body weight; it says metformin should be considered for some high-risk adults. (Source: the ADA’s 2026 Standards of Care.)

What is not in this article?

• The abstract itself. We did not locate the published abstract, so we have not read the authors’ disclosures or funding, which the release says are listed there.
• Confidence intervals. The AHA release does not give them. Some press reports do, but they do not match the release in every detail, so we do not use them.
• Treatment advice. The study does not tell anyone to start, stop or switch a medicine.

What does this mean for a reader?

A single observational abstract does not settle which treatment is better. Decisions about prediabetes depend on a person’s health, weight, risk and goals, and belong with a clinician. Do not stop or change a medicine because of a news article. For the evidence on these drugs, see Best Peptides For’s guides on peptides and type 2 diabetes, semaglutide and tirzepatide. We give no dosing guidance.

U.S. status of GLP-1 drugs and metformin checked Nov. 7, 2026. Based on the AHA news release, not the abstract.