Met-HeFT trial finds no cardiovascular benefit from metformin

The Met-HeFT trial has found that metformin does not significantly reduce the risk of cardiovascular outcomes in patients suffering from heart failure with a reduced ejection fraction who also have diabetes or are at risk for diabetes. The findings were presented at the ESC Congress 2026.

While metformin is the most widely prescribed oral antidiabetic medication globally, researchers noted a historical lack of large-scale, long-term randomized trial evidence regarding its cardioprotective effects. Previous observational studies and smaller trials had suggested potential benefits beyond glucose lowering, but the Met-HeFT trial did not confirm these advantages.

The investigator-initiated, double-blind study was conducted across 23 centers in Denmark as part of the DANHEART project. The trial involved 940 participants with a mean age of 70 years, of whom 16% were women. Over a mean follow-up period of 3.7 years, there was no significant difference between the metformin group and the placebo group regarding the primary endpoint, which included death, worsening heart failure, acute myocardial infarction, or stroke.