Managing Diabetes and Coronary Artery Disease

Diabetes does more than raise blood sugar levels. This chronic condition damages blood vessels, increasing your risk of coronary artery disease (CAD) and life-threatening heart problems.

The Centers for Disease Control and Prevention (CDC) estimates that 1 in 20 Americans have coronary artery disease. It’s the most common type of heart disease in men and women.

Unfortunately, diabetes is a significant coronary artery disease risk factor. The good news? The American Heart Association considers diabetes to be one of the most controllable risk factors.

That’s why endocrinologists (doctors who specialize in diabetes), cardiologists (heart specialists), and primary care providers are working together to manage diabetes and coronary artery disease.

Marie McDonnell, MD, a Mass General Brigham endocrinologist, and George Tolis, MD, a cardiac surgeon, discuss the relationship between the two conditions and how patients can optimize their health. Dr. McDonnell is director of the Diabetes Management Program and Dr. Tolis is section chief of Coronary Surgery and General Cardiac Surgery at Brigham and Women’s Hospital.

“Diabetes specialists are increasingly being called upon to help identify heart disease, and even heart failure, in patients with diabetes,” says Dr. McDonnell. Here’s a look at what’s being done to manage these two chronic conditions.

How diabetes affects blood vessels

Your coronary arteries carry blood, oxygen, and nutrients to your heart. Coronary artery disease occurs when plaque deposits made of cholesterol and other substances build up inside the artery walls. The arteries become less flexible and narrower (arteriosclerosis), limiting how much blood reaches your heart.

“High blood sugar also makes blood vessels less elastic or flexible, which makes it harder for arteries to resist plaque,” says Dr. McDonnell. “It also increases inflammation, which helps cholesterol plaques to form. The longer you have diabetes — even when it’s controlled with medications — the greater the risk for blood vessel, or vascular, damage.”

Diabetes is rarely a solitary disease. It’s common to have other conditions, such as high cholesterol, high blood pressure, or obesity. “Any of these conditions by themselves can damage blood vessels,” says Dr. McDonnell. “But when you have two or more of these conditions, the strain on your cardiovascular system worsens.”

A combination of diabetes and coronary artery disease is especially worrisome. Blood vessel damage from these conditions can cause heart attacks, strokes, and heart failure. Studies show that people with diabetes are up to 4 times more likely to die from heart disease than those who don’t have diabetes. And the same findings indicate that coronary artery disease is the main cause of death in people with diabetes.

Using GLP-1 medications to manage diabetes and protect the heart

Keeping blood sugar levels in a healthy range helps your heart. But good blood sugar control alone isn’t enough. “To truly reduce the risk of a cardiac event, you must manage high cholesterol, high blood pressure, and obesity,” says Dr. McDonnell.

The introduction of GLP-1 agonists improves all conditions. Originally developed as a diabetes treatment, the drugs help your body make insulin, which lowers blood sugar levels. Today, the medications are widely known for their weight loss effects. “Losing weight, particularly with the help of these medications, lowers the three key contributors to heart disease: blood sugar, cholesterol, and blood pressure,” says Dr. McDonnell.

But extra weight is still an independent risk factor for heart disease. A recent study at Mass General Brigham suggests that GLP-1 medications can lower heart disease risk even when you don’t have diabetes. Study participants with obesity (but not diabetes) who took the medication saw a 20% reduction in heart attacks and strokes. A different study found that taking GLP-1 medications after coronary artery bypass grafting lowers the risk of cardiac events in people with obesity and coronary artery disease.

“Whether you’re at a normal weight or overweight, anyone with diabetes can benefit from GLP-1 medications,” says Dr. McDonnell. To protect blood vessels, doctors aim to get A1C readings below 6.5%. An A1C blood test provides an average measurement of the amount of glucose (sugar) in your blood over a period of three months. A reading above 6.5% indicates diabetes.

“We know that blood vessels are healthier and function better when blood sugar levels are below that 6.5% threshold,” says Dr. McDonnell. “Some people need GLP-1s and other diabetes medications to lower blood sugar to a safer level.”

Other ways to protect your heart when you have diabetes

“Your diet plays a key role in controlling blood sugar, and preventing strokes and heart attacks,” says Dr. McDonnell. “Aim for more fresh vegetables, fruits, and lean meats, and less processed foods.”

These heart-healthy lifestyle habits can also help:

• Choose foods that are low in cholesterol, avoid the worst foods for high cholesterol, and be smart about dietary fat.
• Exercise regularly and include strength training.
• Improve your sleep habits.
• Limit alcohol to no more than one drink per day for women, or no more than two drinks per day for men.
• Manage high cholesterol with treatments like cholesterol-lowering medications (statins).
• Seek help to quit smoking.
• Shop with a heart-healthy grocery list.
• Take medications and other steps to achieve a healthy blood pressure.