AFib and Diabetes: What’s the Link?

Medically Reviewed by James Beckerman, MD, FACC on June 28, 2022
4 min read

You’re more likely to develop AFib if you already have diabetes. No one knows for sure whether diabetes causes AFib directly, but it’s a big risk factor. And having both can take an extra toll on your health.

Studies have found that both type 1 and type 2 diabetes likely raise your risk of developing AFib, though the link seems to be greater if you have type 2.

At least one study found that men with type 1 diabetes have a slightly higher than average risk of developing AFib, but females with type 1 are at greater risk with 50% higher chances.

Meanwhile, research shows a strong link between type 2 diabetes and AFib. One analysis of several earlier studies found that people with type 2 diabetes are about 40% more likely to develop AFib. Some studies have suggested the increased risk might be even greater.

Experts don’t think it’s a coincidence. Possible reasons diabetes increases AFib risk include:

Diabetes is a major risk factor for many types of heart disease. Even if you don’t have AFib, having diabetes means you’re twice as likely to have heart disease or stroke as people who don’t have diabetes, and at a younger age.

Several risk factors for AFib and diabetes overlap. These include obesity, high blood pressure, and high cholesterol.

Having diabetes causes physical changes to your body that might cause AFib. Diabetes may cause you to have wide swings in your blood sugar levels, and inflammation in your blood vessels. These changes, in turn, might cause scarring and electrical changes in your heart that could lead to AFib.

Having type 2 diabetes may also increase the amount of fat in the upper chambers of the heart (atria), which might interfere with the signals that allow cells in this area to communicate with each other. Insulin resistance – the body’s inability to use insulin properly, which is what happens in type 2 diabetes – might also cause this problem.

AFib alone is dangerous because it increases your risk of heart failure, blood clots, and stroke. People with AFib are four to six times more likely than others to have a stroke.

Diabetes by itself also significantly raises your risk of heart attack and stroke, in addition to other problems, including kidney disease, foot problems, eye disease, and nerve damage. When you have diabetes and AFib together, you’re more likely to:

  • Have worse symptoms and an overall lower quality of life compared to those who only have AFib
  • Have a stroke
  • Die prematurely for any reason (including, but not limited to, heart disease or stroke)
  • Be unaware you’re having AFib symptoms. If you don’t feel symptoms, you might not realize your AFib is getting worse or that it’s not properly controlled. It also suggests that there may be some people with diabetes who have AFib but haven’t been diagnosed.

Take your medications as directed. It’s important to take any medications your doctor has prescribed to control your AFib. Those probably include a blood thinner (to reduce the risk of clots) as well as a blood pressure drug to lower your heart rate.

If you also have type 2 diabetes, it’s possible that metformin or other glucose-lowering drugs might help both your diabetes and your AFib. Some early research suggests that metformin might have properties that help stabilize an irregular heartbeat. Research has also found that people with diabetes who take metformin or a diabetes drug in the TZD class might be less likely to later develop AFib for the first time.

Keep close tabs on your blood sugar. Diabetes is most dangerous when it’s not well-controlled. In fact, research has shown that people with type 2 diabetes who have good glycemic control only have a slightly increased risk of developing AFib, but those who have poor control of their blood sugar are at high risk.

Other research has found that keeping blood sugar levels healthy also matters for people who already have AFib. One study found that people who had AFib as well as type 2 diabetes for 10 years or less were less likely to have a blood clot (including the kind that could block blood flow to the brain and cause a stroke) if their A1c levels were 6.5% or lower, compared with those with higher A1c levels.

Get plenty of physical activity. A recent study found that people with diabetes who regularly did moderate to vigorous exercise were less likely to develop AFib. The same study also found that nonsmokers and those who drank only a little alcohol were less likely to develop Afib than were smokers and those who drank more alcohol.

Maintain a healthy weight. Research has found that obesity might increase your risk of AFib by as much as 50%. But losing just 10% of your body weight if you already have AFib may lessen the severity of your heart condition. Obesity is also a well-known risk factor for type 2 diabetes.