DALLAS — Adults with prediabetes and obesity who took GLP-1 medications were more likely to return their blood sugar to normal levels, and less likely to develop Type 2 diabetes, have a heart attack or stroke, or die over five years, than similar adults who took the standard prevention drug metformin, according to large new preliminary research released on 2 November 2026.
The study, led by researchers at Mayo Clinic in Scottsdale, Arizona, reviewed the electronic health records of 256,492 adults with prediabetes and obesity. It is among the largest comparisons yet of GLP-1 medications and metformin at the prediabetes stage — the window before blood sugar rises high enough for a diabetes diagnosis, when progression can still often be reversed. The findings were announced on 2 November 2026 ahead of presentation at the American Heart Association's Scientific Sessions 2026, which runs from 6 to 9 November in Chicago.
Illustration: A doctor discusses blood sugar results with a patient in a clinic. This is an illustration, not a photograph of a real event.
What Happened
Researchers compared two groups of adults with prediabetes and obesity: about half were taking a GLP-1 medication — semaglutide, tirzepatide, liraglutide or dulaglutide — and the other half were taking metformin, the long-established first-line drug for prediabetes and Type 2 diabetes. The health records came from the TriNetX global electronic health record network, covering 104 institutions, with data from 2010 to 2023 and an average follow-up of roughly three years.
Compared with those taking metformin, people taking GLP-1 medications had a 1.5 times higher chance of reversing high blood sugar to normal levels, a 31 percent lower risk of developing Type 2 diabetes, and a 41 percent lower risk of death from any cause, the researchers reported. They were also associated with 15 percent fewer heart attacks, 20 percent fewer strokes, 25 percent fewer cases of heart failure and 8 percent fewer cases of atrial fibrillation, a common irregular heartbeat.
The study's lead author, Vinicius de Sousa Barzon Serra, a research fellow in cardiovascular medicine at Mayo Clinic in Scottsdale, said the results could change conversations between doctors and patients about when to consider GLP-1 medications. "The great news with prediabetes is that it is still possible to reverse the progression of the disease," Serra said. "This research may add to the case for considering GLP-1 medications earlier for certain patients, rather than waiting until they develop Type 2 diabetes."
Serra was careful to frame the finding as an addition to, not a replacement for, existing care. "Metformin is still a first-line treatment choice. It is safe, inexpensive and has a long track record. This is less about replacing one medication with another and more about discussing additional options with specific patients," he said.
Background
Prediabetes means blood sugar levels are above normal but not yet high enough to be diagnosed as Type 2 diabetes. Nearly 40 percent of adults in the United States have prediabetes, according to the American Heart Association's 2026 Heart Disease and Stroke Statistics. Up to 10 percent of those adults progress to Type 2 diabetes each year, according to statistics from the National Institutes of Health cited by the researchers.
Most earlier research on GLP-1 medications focused on people who already had Type 2 diabetes. These drugs, originally developed for diabetes and now widely used for weight management, work in part by mimicking a gut hormone that helps control blood sugar and appetite. Metformin, by contrast, has been the standard first-line option for decades, usually alongside lifestyle changes such as healthier eating and more physical activity.
In this analysis, the average participant was 52 years old and 76 percent were women. To make the comparison fairer, researchers matched patients with similar ages, health conditions — such as high blood pressure, sleep apnoea or nicotine dependence — and other medications, so that differences in outcomes were more likely to reflect the medication itself than differences between the groups.
About 1 in 10 adults in the United States may take a GLP-1 medication for blood sugar control or weight loss, according to 2026 healthcare survey information from more than 2,800 hospitals and health systems nationwide cited in the announcement. That widespread use makes the prediabetes question urgent: if the drugs help earlier, millions of people at risk could benefit — but cost and access remain major barriers.
Illustration: A GLP-1 injection pen beside a healthy heart and a blood sugar gauge in the normal range. This is an illustration, not a photograph of a real event.
Why It Matters
The stakes go well beyond a single blood test. Type 2 diabetes sharply raises the risk of heart disease, stroke, kidney failure, vision loss and nerve damage, and it is expensive to treat once established. Preventing progression — or reversing prediabetes altogether — avoids not only diabetes itself but also much of the cardiovascular damage that follows it.
That is why the heart findings matter as much as the blood sugar results. Fewer heart attacks, strokes and cases of heart failure in the GLP-1 group suggest the benefit is not only about glucose control. Robert Eckel, a past volunteer president of the American Heart Association who was not involved in the study, said the pattern was not surprising. "The benefits noted in this study likely relates to the patients losing weight, which is known to help prevent Type 2 diabetes," said Eckel, professor of medicine emeritus at the University of Colorado Anschutz Medical Campus. "Preventing the progression from prediabetes to Type 2 diabetes keeps patients from having Type 2 diabetes, and it also helps prevent heart attack and strokes. GLP-1s provide another option for prevention, perhaps as an add-on therapy."
Eckel also flagged the practical limits. "However, costs and access to these medications are important factors," he said. GLP-1 medications are far more expensive than metformin, which costs pennies a day as a generic, and supply and insurance coverage vary widely. Any shift toward earlier use would therefore raise difficult questions about who gets treated first and who pays.
The findings also arrive at a moment when diabetes prevention is under renewed scrutiny. With nearly 40 percent of American adults living with prediabetes, most of them unaware of it, researchers say the bigger public health challenge may be detection: people cannot be treated for a condition they do not know they have. Screening, lifestyle support and affordable medication together — rather than any single drug — remain the foundation of prevention.
What Happens Next
The research will be presented at the American Heart Association's Scientific Sessions 2026 in Chicago from 6 to 9 November, where other researchers will be able to question the methods and results in detail. Because the findings come from a conference abstract, they are preliminary: abstracts presented at the association's meetings are not peer-reviewed, and the results are considered provisional until published as a full manuscript in a peer-reviewed journal.
The study also has important limitations that its authors acknowledge. It was observational, so it cannot prove that GLP-1 medications caused the better outcomes — only that the two groups differed. Patients and outcomes were identified through diagnosis codes, which can be incomplete; researchers relied on prescription records, so how consistently patients actually took their medication, or at what dose, is not reflected; and GLP-1 medications were grouped together, so differences between individual drugs were not examined.
Doctors say patients should not change their own treatment on the basis of a single preliminary study. Serra himself stressed that lifestyle change remains essential: "It is important to note that an essential component of prediabetes treatment is lifestyle changes to manage weight, including diet and exercise and considering medications, including metformin, based on each individual's overall health and any other medical conditions."
If the findings hold up in peer review and in future trials designed to test cause and effect, guidelines for prediabetes care could eventually shift toward earlier discussion of GLP-1 options for selected patients — particularly those with obesity and high cardiovascular risk. For now, the study's clearest message is about timing: prediabetes is a stage when action still works, and the earlier that action starts, the more it can prevent.
Illustration: A person walking outdoors with fresh vegetables and a water bottle at sunrise. This is an illustration, not a photograph of a real event.
Health note: This article reports on preliminary research findings for general information only and is not medical advice. Anyone concerned about blood sugar, diabetes risk or medication should speak to their own doctor.
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FAQ
What is prediabetes?
Prediabetes is a condition in which blood sugar levels are higher than normal but not high enough for a diagnosis of Type 2 diabetes. It often has no symptoms, and many people do not know they have it. Without intervention, up to 10 percent of adults with prediabetes progress to Type 2 diabetes each year.
What did the new study compare?
The study compared GLP-1 medications (semaglutide, tirzepatide, liraglutide or dulaglutide) with metformin in 256,492 adults with prediabetes and obesity, using electronic health records from 104 institutions between 2010 and 2023, with an average follow-up of about three years.
How much better were GLP-1 medications in the study?
Compared with metformin, GLP-1 users had a 1.5 times higher chance of returning blood sugar to normal, a 31 percent lower risk of developing Type 2 diabetes, a 41 percent lower risk of death from any cause, and fewer heart attacks (15 percent), strokes (20 percent), heart failure cases (25 percent) and atrial fibrillation cases (8 percent).
Does this mean metformin should be replaced?
No. The study's lead author said metformin remains a safe, inexpensive first-line treatment with a long track record. The findings suggest GLP-1 medications could be discussed as an additional option for certain patients, not as an automatic replacement.
Are these findings final?
Not yet. The research is a conference abstract presented ahead of the American Heart Association's Scientific Sessions 2026. It is observational and has not been peer-reviewed, so it cannot prove cause and effect and is considered preliminary until published in full.
Sources
- American Heart Association news release, "GLP-1 meds linked to lower diabetes, heart risks than standard diabetes prevention med," 2 November 2026 (via FinancialContent / NewMediaWire).
- American Heart Association, 2026 Heart Disease and Stroke Statistics (prediabetes prevalence figure).
- National Institutes of Health statistics on annual progression from prediabetes to Type 2 diabetes, as cited in the study announcement.
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