An analysis of health records from more than 256,000 adults with obesity and prediabetes found that people prescribed GLP-1 medicines were less likely to develop Type 2 diabetes over roughly three years than a similar group taking metformin, researchers say. The preliminary findings are being presented at the American Heart Association’s Scientific Sessions in Chicago, which run Nov. 6-9.

The study compared patients taking GLP-1 medicines, including semaglutide and tirzepatide, with patients taking metformin. Researchers reported a 31% lower risk of progressing to Type 2 diabetes and a 1.5-times higher chance of returning to normal blood sugar levels among the GLP-1 group. The analysis also found lower rates of several cardiovascular outcomes.

These results show an association, not proof that the drugs caused the difference. The researchers used electronic health records and matched patients on some characteristics, but the study was observational; medication doses and how consistently people took them were not captured, and several GLP-1 medicines were grouped together.

The American Heart Association says the conference abstract has not been peer-reviewed and should be considered preliminary until a full paper is published. A study author said metformin remains a first-line option with a long safety record, while treatment choices depend on a person’s health and should be discussed with a clinician.

Sources: Reuters; American Heart Association.