Diabetes is a disease in which the body doesn’t produce or properly use insulin, a hormone produced in the pancreas that turns sugar (glucose) and other nutrients into energy. Over time, too much glucose in the blood damages nerves and blood vessels. This, in turn, can cause coronary artery disease (CAD), and stroke, two forms of cardiovascular disease (CVD). If you have diabetes, you’re twice as likely to have heart disease or a stroke than someone who doesn’t have diabetes—and at a younger age.1 In addition, damage to the blood vessels in the legs can result in poor circulation and increase the risk of foot ulcers and amputations, while damage to the blood vessels that supply blood to the kidney can cause kidney failure and damage to the small blood vessels in the eye can eventually cause blindness.
The relationship between diabetes and CVD is clear, but the causes are complex. High blood glucose levels don’t fully explain the relationship between diabetes and CVD. People with diabetes also tend to have low-level inflammation of the lining of the arteries, which can interfere with the proper function of the blood vessels and make them more susceptible to developing atherosclerotic plaque, where cholesterol and other substances build up in the arteries, limiting the flow of blood to the heart.
With diabetes, there’s also a greater tendency for blood cells to clump together to form blood clots within the blood vessels. A blood clot that blocks the arteries supplying blood to the heart causes a heart attack, while a blood clot that blocks an artery supplying blood to the brain causes a stroke.
Diabetes and CVD risk factors
The blood vessels in patients with diabetes are also more vulnerable to the harmful effects of other CVD risk factors. People with diabetes are more likely to have certain risk factors that increase their chances of developing CVD. These risk factors include the following:
- High blood pressure
- Abnormal blood lipids (high LDL or "bad" cholesterol, high triglycerides, and low HDL or "good" cholesterol)
- Lack of physical activity
- Poorly controlled blood glucose levels
- Insulin resistance (common in type 2 diabetes)
Diabetes and diagnosing CVD
If you have diabetes, your doctor will assess your risk for CVD by asking questions about your family history, diet, exercise, stress level, and whether you smoke. Your doctor will also check your blood pressure and body weight and order or review key blood tests. These blood tests may include the following:
- Cholesterol – This test includes total, HDL, and LDL cholesterol levels.
- Triglycerides – This test is a kind of fat often elevated in people with diabetes.
- Hemoglobin A1C – This test measures average blood glucose levels over time.
- High-sensitivity C-reactive protein (CRP) – This test measures inflammation in your body and blood vessels.
Your doctor may also want you to have certain diagnostic tests. These tests may include the following:
- Electrocardiogram (ECG/EKG) – This test records the electrical activity in your heart and can detect abnormalities that suggest the heart may not be getting enough blood flow in certain areas.
- Coronary calcium score – This test is performed as part of a computerized tomography (CT) scan and helps your doctor determine your risk for developing serious heart disease by measuring the amount of calcified plaque in your arteries.
If your initial test results indicate an increased risk for CVD or if you’re having worrisome symptoms such as chest pain or unexpected shortness of breath during physical activity, your doctor may refer you for further testing. This further testing may include the following:
- Stress test – This test evaluates how much blood flow is getting to the heart and how effectively the heart is pumping during exercise or another type of physical stress.
- Echocardiogram (echo) – This test uses ultrasound to evaluate how well the heart is pumping and whether the heart muscle has become abnormally thick due to high blood pressure.
- Coronary angiography – This test involves threading a slender, flexible tube called a catheter into the arteries of your heart and injecting X-ray dye to enable an interventional cardiologist to see inside your arteries, find any plaques, and measure how severe they are.
If your doctor suspects cholesterol plaque is clogging the arteries in your legs or body organs, other diagnostic tests may be needed. Testing for plaque may include the following tests:
- Ultrasound – This test uses sound waves to evaluate blood flow through the arteries.
- Noninvasive angiography – This test uses CT or magnetic resonance imaging (MRI) to create detailed images of the arteries without placing any instruments or tubes into the body.
- Peripheral angiography – This test is similar to coronary angiography but involves arteries that supply blood to organs other than the heart.
- Ankle-brachial index (ABI) – This test helps diagnose peripheral artery disease (PAD) in the legs and determine its severity. During an ABI test, your doctor will use a blood pressure cuff and a special ultrasound probe to compare blood pressure readings in the arm and lower leg on the same side of the body to determine if a blockage is interfering with blood flow to the lower leg.
Did you know?
- Hispanic adults are 70% more likely than non-Hispanic white adults to be diagnosed with diabetes.2
- Black adults are 60% more likely than non-Hispanic white adults to be diagnosed with diabetes.2
- Asian Americans are 40% more likely to be diagnosed with diabetes than non-Hispanic whites.2
- American Indian/Alaska Native adults are almost 3 times more likely than non-Hispanic white adults to be diagnosed with diabetes.2
- In 2018, Native Hawaiians/Pacific Islanders were 2.5 times more likely to be diagnosed with (and to die from) diabetes than non-Hispanic whites.2
- From 2017-2018, Asian Indians were 70% more likely to be diagnosed with diabetes than non-Hispanic whites.2
- In 2019, non-Hispanic blacks were 2.5 times more likely to be hospitalized with diabetes and associated long-term complications than non-Hispanic whites.2
- In 2019, non-Hispanic blacks were twice as likely as non-Hispanic whites to die from diabetes.2
- In 2018, Hispanics were 1.3 times more likely than non-Hispanic whites to die from diabetes.2
- In 2018, American Indians/Alaska Natives were 2.3 times more likely than non-Hispanic whites to die from diabetes.2
- In 2014, American Samoans had the highest diabetes rate among surveyed Pacific Islander sub-populations—their rate was 2.8 times higher than the U.S. white population.2
Are you at risk?
Learn more about your risk and how to reduce your risk factors.