Popular Weight-Loss Drugs Linked to 31% Lower Diabetes Risk in Prediabetes: Large Study

Adults with prediabetes and obesity who took GLP-1-based medications had a 31% lower risk of developing type 2 diabetes and a 41% lower risk of death compared with those taking metformin, a large observational study has found.

The findings are set to be presented at the American Heart Association's (AHA) Scientific Sessions 2026 this weekend in Chicago. They have not yet undergone the full peer review process.

The study involved health records for 256,492 adults with prediabetes and obesity, averaging 52 years of age. Approximately half of the group received GLP-1 medications – including semaglutide, tirzepatide, liraglutide and dulaglutide – and half received metformin. Metformin is an oral medication used primarily to treat type 2 diabetes, widely considered the first-line treatment, and is also sometimes prescribed to people with prediabetes to help prevent or delay progression.

Based on a three-year follow-up, in addition to the lower risk of diabetes and all-cause mortality, GLP-1-based medications were associated with 20% fewer strokes, 15% fewer heart attacks and 25% fewer cases of heart failure.

Study author Vinicius de Sousa Barzon Serra, M.D., a research fellow in the department of cardiovascular medicine at the Mayo Clinic in Scottsdale, Arizona, said: 'The 41% lower risk of death from any cause surprised me most.' He added that he had expected GLP-1 medications to do better than metformin on blood sugar and diabetes risk because they lead to much more weight loss, and that he was also struck that the benefit appeared across many outcomes, including heart attack, stroke, heart failure and atrial fibrillation.

Nearly 40% of US adults have prediabetes, according to statistics from the AHA. That condition is marked by blood sugar levels that are above normal but not yet elevated enough for a diabetes diagnosis. As many as 10% of those with prediabetes will go on to develop type 2 diabetes each year.

'Most earlier research on these medications focused on people who already had diabetes,' Serra noted. 'Our study suggests the prediabetes stage may be an important time to consider them, rather than waiting until they develop type 2 diabetes.'

The study did have limitations. While it found a link between GLP-1 medications and better health outcomes, it does not prove that the drugs were responsible. The findings are preliminary until published in a peer-reviewed journal, Serra noted. He said the researchers matched patients by age, health conditions and other characteristics to make the groups comparable, but other differences between the groups may remain, and because the GLP-1 medications were grouped together, the study could not tell whether individual drugs differ.

The study relied on patients' electronic health records, which may have contained missing or incorrect information. Factors not measured in the study, such as medication dosage and compliance, could also have influenced the results, the researchers noted.

Serra advised people with prediabetes and obesity to talk with their doctor about all their options and not to stop or change any medication on their own. He emphasised that metformin is a safe, inexpensive option with a long track record, and that lifestyle changes such as healthy eating, regular physical activity and weight management remain the foundation of treatment. For some patients, a GLP-1 medication may be worth discussing depending on their overall health, other medical conditions, cost and access, and the decision should be made together with their doctor.