About a third of people with coronary artery (heart) disease have thickening of the heart muscle (called left ventricular hypertrophy or LVH), which is associated with a poorer outcome in these patients. High blood pressure, insulin resistance, and obesity all play a role in the development of LVH. Metformin, a diabetes treatment, reduces insulin resistance. Ergo, a recent study investigated whether metformin may help to ‘remodel’ the heart to improve LVH.
The MET-REMODEL study , published in the European Heart Journal, examined the effect of metformin 1000mg twice daily vs placebo on LVH in 68 patients with coronary artery disease and insulin resistance, but without diabetes (of note, about 75% of these patients had prediabetes).
After one year, metformin treatment significantly improved LVH (as manifested by a reduction in left ventricular mass index on cardiac MRI). People in the metformin group also had a reduction in body weight, subcutaneous fat (fat under the skin), systolic blood pressure, and measures of oxidative stress compared with placebo.
In the type 2 diabetes world, there is some evidence that metformin may reduce the risk of cardiovascular disease. It is interesting to consider that metformin may have a cardiac benefit in people without diabetes. Prediabetes, in particular impaired glucose tolerance, carries a cardiovascular risk that approximates the cardiovascular risk in people with diabetes, so perhaps the benefits of metformin in diabetes are also enjoyed by the prediabetes population. Interestingly, metformin did not have a significant impact on insulin resistance in this study, but this may have been related to the small size of the study.
Further study is currently underway to test the potential cardiac benefits of metformin in people with prediabetes and established cardiovascular disease.
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