Metformin offers limited heart health benefits for people without diabetes

The widely used diabetes drug metformin does not lower the risk of cardiovascular disease in people without diabetes, a new study has found.
Previous research showed that the first-line drug treatment for type 2 diabetes reduces the long-term risk of heart attack by a 40% in diabetic patients
To examine whether the medication can have similar cardiovascular benefits on the general public, Dr. David Preiss from the University of Glasgow and colleagues conducted a double blind trial of 173 non-diabetic individuals taking statins for heart disease.
They investigated the effects of metformin on markers of atherosclerosis (hardening of the arteries), which usually indicates a future risk of heart attack and stroke.
Patients were put on a regimen of metformin or placebo, and after 18 months the researchers found there was no statistically significant improvement in the carotid intima-media thickness (cIMT), an established marker of atherosclerosis and cardiovascular risk, of those taking metofrmin compared to the placebo group.
Metformin treatment did lead to better improvements in risk factors for type 2 diabetes, including lower HbA1c levels and decreases in all measures of adiposity (body weight, body fat, BMI and waist circumference).
However, it also caused more adverse events than the placebo, with diarrhoea, nausea and vomiting more common amongst the metformin patients.
“Major cardiovascular outcome trials are needed to conclusively assess metformin’s cardiovascular effects in people without type 2 diabetes – such trials are underway at present,” Dr. Preiss concluded.
“We cannot dismiss the potential cardiovascular benefit of metformin in patients without diabetes, but this study suggests that metformin has limited impact on important cardiovascular risk factors when patients are already on a statin.”
The results of the Carotid Atherosclerosis: Metformin for Insulin Resistance (CAMERA) trial were published online in The Lancet Diabetes and Endocrinology.