The study, called the MET-REMODEL Trial, suggests that metformin can reduce left ventricular hypertrophy (LVH) in people who have prediabetes.
It’s the first clinical trial to show that metformin can reverse this heart condition.
Researchers did note that larger trials are needed to confirm the cardio-protective role of metformin.
Metformin has been on the market in the United States since 1995. Wendy Gregor, MA, RDN, CDE, a registered dietitian nutritionist and certified diabetes educator at Cecelia Health in New York, said this provides researchers with a lot of information on how metformin works.
“With type 2 diabetes, the liver doesn’t get the message to stop making sugar when blood sugar is already high. Metformin helps correct this problem and slows liver sugar production,” Gregor told Healthline.
Dr. Nieca Goldberg, a cardiologist and the medical director of the Joan H. Tisch Center for Women’s Health at the NYU Langone Medical Center, said there is a connection between diabetes, blood pressure, and LVH.
“People can develop LVH from untreated high blood pressure, which may also cause narrowing of the aortic valve, also called aortic stenosis,” Goldberg told Healthline. “High blood pressure is very prevalent in the U.S. and data shows only 20 percent are actually controlled, so an important way to prevent LVH is by maintaining healthy blood pressure.”
According to Goldberg, you can have LVH and not experience symptoms until the condition becomes much more serious. Then “you can develop shortness of breath, decreased endurance, and chest discomfort.”
“People with a strong family history of LVH are most at risk, and while not everyone with a genetic predisposition will get it, these are the people who should be most carefully screened,” she noted.
In severe cases, she said, “blood flow from the heart becomes sufficiently obstructed that a person can faint, and it becomes life-threatening. It’s been associated with increased risk of atrial fibrillation (irregular heartbeat) and sudden death.”
A 2016 analysis of more than 200 studies, which included nearly 1.5 million participants, found that metformin reduced the risk of people dying from heart disease by between 30 and 40 percent compared to sulfonylurea, a drug also used to reduce blood sugar levels.
“Metformin looks like a clear winner. This is likely the biggest bit of evidence to guide treatment of type 2 diabetes for the next two to three years,” Dr. Nisa Maruthur, MHS, lead author of the 2016 study and an assistant professor of medicine at the Johns Hopkins University School of Medicine in Maryland, said in a statement.
While metformin has a long track record of safety and effectiveness, use of the drug may come with side effects.
In fact, side effects on the digestive tract have led a number of people with diabetes to stop taking the medication.
“The most common side effects of metformin are gastrointestinal disturbances such as nausea, vomiting, gas, diarrhea, and stomach upset,” Gregor said. “Taking metformin with food can help reduce these symptoms.”
According to the National Institutes of Health, people who use metformin may also experience more serious symptoms such as:
- a metallic taste in the mouth
- nail changes
- muscle pain
However, there’s an extended-release version of the drug that reduces the chance of experiencing these side effects.
“Extended-release metformin can decrease these side effects, and the once-daily dosing is more convenient and may result in fewer missed doses,” Gregor noted.
Metformin is inexpensive, safe, and effective. But it may cause uncomfortable side effects in the digestive tract. This can often be avoided by using the extended-release version of the drug.