A study of more than a quarter million adults with prediabetes and obesity has linked Ozempic-style drugs to fewer heart attacks and strokes than metformin, a widely used diabetes pill.1 The results were presented at the American Heart Association’s Scientific Sessions 2026 and have not yet been peer reviewed or published in a journal.1 Because the researchers looked back at health records rather than running a controlled trial, the study shows a link, not proof that the drugs caused the difference.1
What happened
Researchers analyzed the electronic health records of 256,492 adults with prediabetes and obesity, drawn from the TriNetX global health network.1 Prediabetes means blood sugar is higher than normal but not yet high enough for a type 2 diabetes diagnosis.1 The people in the study had an average age of 52, and 76% were women.1
The team compared people who were prescribed GLP-1 drugs, the class that includes Ozempic, with people prescribed metformin.1 The drugs counted in the GLP-1 group were semaglutide, tirzepatide, liraglutide and dulaglutide.1 Semaglutide is sold as Ozempic and tirzepatide as Mounjaro.2
The lead author is Vinicius de Sousa Barzon Serra, a research fellow in the Department of Cardiovascular Medicine at Mayo Clinic in Scottsdale, Arizona.1
What the study measured
Compared with people on metformin, people on Ozempic-style drugs had:1
- 15% fewer heart attacks
- 20% fewer strokes
- 25% fewer cases of heart failure
- an 8% lower risk of atrial fibrillation, an irregular heartbeat
- a 31% lower risk of developing type 2 diabetes
- a 41% lower risk of death from any cause
They were also about 1.5 times more likely to bring their blood sugar back to normal levels.1
Serra said the death figure surprised him most. “The finding that surprised me most was the 41 percent lower risk of death from any cause,” he told Newsweek.1 He said he had expected the drugs to beat metformin on blood sugar and diabetes risk because they lead to much more weight loss, and that weight loss alone might not fully explain the gap in deaths.1
“What also stood out is that the benefit was not limited to blood sugar. It showed up across heart attacks, strokes, heart failure, and even atrial fibrillation, in the same direction.”
That was Serra speaking to Newsweek.1 He also noted that most earlier research had focused on people who already had type 2 diabetes, while this study looked at people with prediabetes and obesity, “when it is still possible to prevent the disease.”1
What it does not show yet
The researchers themselves cautioned that the study was observational and relied on health records, so it cannot prove that the drugs directly caused the better outcomes.1 Factors other than the medications may have contributed to the differences between the two groups.1
Bradley Neutel, a board-certified endocrinologist and founder of Coastline Endocrinology who was not involved in the research, made the same point.1 “Observational studies like this are better than nothing, and certainly provide some helpful associations, but they are not as definitive as rigorous trials,” he told Newsweek.1 He said overall health, lifestyle, access to health care and the tendency to take medications may differ between people prescribed GLP-1 drugs and people prescribed metformin.1 He also named age, how severe a person’s obesity is, other illnesses such as heart disease, and other medications as factors that need to be considered.1
Several other things are not yet known from the available reports:
- The full methods and data have not been published, because the work so far is a conference abstract.1
- The reports do not say how long people stayed on each drug or how results differed between the individual drugs grouped together.1
- Three in four people in the study were women, so the results may not apply equally to everyone.1
Who is behind it
The study was led from Mayo Clinic and used records from the TriNetX network.1 The coverage available to Biohack does not say who funded the work or whether any authors have ties to the companies that make these drugs. Those details usually appear when a study is published in full.
Drugmakers also publish their own research on the heart safety of these medicines. Novo Nordisk, for example, runs a portal it calls Science Hub, which it describes as its one-stop site for its scientific publications and clinical trials, aimed at healthcare professionals.3 The new Mayo study was not presented as company research.
Serra said the findings should not replace existing care. “Metformin is still a safe, low-cost, first-line option and lifestyle changes remain the foundation of treatment,” he said.1 He added that in his view prediabetes “may be a good time to talk about GLP-1 medications with some patients, instead of waiting for diabetes to develop.”1 That is the author’s opinion, not a conclusion the study design can prove.
How it fits with earlier research
Earlier studies have also tied these drugs to heart benefits, in different groups of people. A controlled trial called SELECT, published in the New England Journal of Medicine in 2023, tested semaglutide in people with obesity.2 It reported that the risk of heart attacks, strokes and other major heart events was about 20% lower than in people given a placebo (a dummy treatment).2 People in SELECT saw heart benefits even if they did not lose weight, according to Melanie Jay, who directs NYU Langone’s Comprehensive Program on Obesity.2 “It means there’s weight dependent and weight independent effects on the heart,” she said.2
In March 2026, a study in the journal BMJ Medicine looked at records of more than 333,000 US veterans with type 2 diabetes.2 People who took GLP-1 drugs for an average of three years without stopping had about an 18% lower risk of heart attacks, strokes or death than people on sulfonylureas, an older type of diabetes pill.2 That study also found that the benefit faded after people stopped: heart risks were 4% higher six months after stopping, 14% higher at one year and 22% higher by the second year, compared with people who stayed on the drug.2 Roughly half of people who start these drugs stop within a year, according to that report.2
How the drugs might help the heart is still unclear. Weight loss, which helps reduce inflammation, may be a major driver, and the heart itself has receptors for GLP-1, so there may also be a direct effect on heart tissue, Jay said.2
The new study adds a different group to this picture: people who do not yet have diabetes. Nearly 40% of US adults have prediabetes, and up to 10% progress to type 2 diabetes each year, according to the American Heart Association.1
What to watch next
- Full publication. The study has not yet been peer reviewed or published in a journal.1 A full paper should show the methods, how the two groups were matched, and any funding or conflicts of interest.
- Controlled trials in prediabetes. Neutel’s point that records studies are not as definitive as rigorous trials means a trial that randomly assigns people with prediabetes to each drug would be the stronger test.1
- Staying on the drugs. The veterans study suggests heart benefits may depend on continued use, which matters given how many people stop.2
This article reports research findings and is not medical advice.
