Diabetic Heart Disease
What Is Diabetic Heart?
The term "diabetic heart disease" (DHD) refers to heart disease that develops in people who have diabetes. Compared with people who don't have diabetes, people who have diabetes:
- Are at higher risk for heart disease
- Have additional causes of heart disease
- May develop heart disease at a younger age
- May have more severe heart disease
What Is Diabetes?
Diabetes is a disease in which the body's blood glucose (sugar) level is too high. Normally, the body breaks down food into glucose and carries it to cells throughout the body. The cells use a hormone called insulin to turn the glucose into energy.
The two main types of diabetes are type 1 and type 2. In type 1 diabetes, the body doesn't make enough insulin. This causes the body's blood sugar level to rise.
In type 2 diabetes, the body's cells don't use insulin properly (a condition called insulin resistance). At first, the body reacts by making more insulin. Over time, though, the body can't make enough insulin to control its blood sugar level.
What Heart Diseases Are Involved in Diabetic Heart Disease?
DHD may include coronary heart disease (CHD), heart failure, and/or diabetic cardiomyopathy.
Coronary Heart Disease
In CHD, a waxy substance called plaque builds up inside the coronary arteries. These arteries supply your heart muscle with oxygen-rich blood.
Plaque is made up of fat, cholesterol, calcium, and other substances found in the blood. When plaque builds up in the arteries, the condition is called atherosclerosis.
Plaque narrows the coronary arteries and reduces blood flow to your heart muscle. The buildup of plaque also makes it more likely that blood clots will form in your arteries. Blood clots can partially or completely block blood flow.
CHD can lead to chest pain or discomfort called angina, irregular heartbeats called arrhythmias, a heart attack, or even death.
Heart failure is a condition in which your heart can't pump enough blood to meet your body's needs. The term “heart failure” doesn't mean that your heart has stopped or is about to stop working. However, heart failure is a serious condition that requires medical care.
If you have heart failure, you may tire easily and have to limit your activities. CHD can lead to heart failure by weakening the heart muscle over time.
Diabetic cardiomyopathy is a disease that damages the structure and function of the heart. This disease can lead to heart failure and arrhythmias, even in people who have diabetes but don't have CHD.
People who have type 1 or type 2 diabetes can develop DHD. The higher a person's blood sugar level is, the higher his or her risk of DHD.
Diabetes affects heart disease risk in three major ways.
First, diabetes alone is a very serious risk factor for heart disease, just like smoking, high blood pressure, and high blood cholesterol. In fact, people who have type 2 diabetes have the same risk of heart attack and dying from heart disease as people who already have had heart attacks.
Second, when combined with other risk factors, diabetes further raises the risk of heart disease. Although research is ongoing, it's clear that diabetes and other conditions—such as overweight and obesity and metabolic syndrome—interact to cause harmful physical changes to the heart.
Third, diabetes raises the risk of earlier and more severe heart problems. Also, people who have DHD tend to have less success with some heart disease treatments, such as coronary artery bypass grafting and percutaneous coronary intervention, also known as coronary angioplasty.
If you have diabetes, you can lower your risk of DHD. Making lifestyle changes and taking prescribed medicines can help you prevent or control many risk factors.
Taking action to manage multiple risk factors helps improve your outlook. The good news is that many lifestyle changes help control multiple risk factors. For example, physical activity can lower your blood pressure, help control your blood sugar level and your weight, and reduce stress.
It's also very important to follow your treatment plan for diabetes and see your doctor for ongoing care.
If you already have DHD, follow your treatment plan as your doctors advises. This may help you avoid or delay serious problems, such as a heart attack or heart failure.
At least four complex processes, alone or combined, can lead to diabetic heart disease (DHD). They include coronary atherosclerosis; metabolic syndrome; insulin resistance in people who have type 2 diabetes; and the interaction of coronary heart disease (CHD), high blood pressure, and diabetes.
Researchers continue to study these processes because all of the details aren't yet known.
Atherosclerosis is a disease in which plaque builds up inside the arteries. The exact cause of atherosclerosis isn't known. However, studies show that it is a slow, complex disease that may start in childhood. The disease develops faster as you age.
Coronary atherosclerosis may start when certain factors damage the inner layers of the coronary (heart) arteries. These factors include:
- High amounts of certain fats and cholesterol in the blood
- High blood pressure
- High amounts of sugar in the blood due to insulin resistance or diabetes
Plaque may begin to build up where the arteries are damaged. Over time, plaque hardens and narrows the arteries. This reduces the flow of oxygen-rich blood to your heart muscle.
Eventually, an area of plaque can rupture. When this happens, blood cell fragments called platelets stick to the site of the injury. They may clump together to form blood clots.
Blood clots narrow the coronary arteries even more. This limits the flow of oxygen-rich blood to your heart and may worsen angina (chest pain) or cause a heart attack.
Metabolic syndrome is the name for a group of risk factors that raises your risk of both CHD and type 2 diabetes.
If you have three or more of the five metabolic risk factors, you have metabolic syndrome. The risk factors are:
- A large waistline (a waist measurement of 35 inches or more for women and 40 inches or more for men).
- A high triglyceride level (or you’re on medicine to treat high triglycerides). Triglycerides are a type of fat found in the blood.
- A low HDL cholesterol level (or you're on medicine to treat low HDL cholesterol). HDL sometimes is called "good" cholesterol. This is because it helps remove cholesterol from your arteries.
- High blood pressure (or you’re on medicine to treat high blood pressure).
- A high fasting blood sugar level (or you're on medicine to treat high blood sugar).
It's unclear whether these risk factors have a common cause or are mainly related by their combined effects on the heart.
Obesity seems to set the stage for metabolic syndrome. Obesity can cause harmful changes in body fats and how the body uses insulin.
Chronic (ongoing) inflammation also may occur in people who have metabolic syndrome. Inflammation is the body's response to illness or injury. It may raise your risk of CHD and heart attack. Inflammation also may contribute to or worsen metabolic syndrome.
Research is ongoing to learn more about metabolic syndrome and how metabolic risk factors interact.
Insulin Resistance in People Who Have Type 2 Diabetes
Type 2 diabetes usually begins with insulin resistance. Insulin resistance means that the body can't properly use the insulin it makes.
People who have type 2 diabetes and insulin resistance have higher levels of substances in the blood that cause blood clots. Blood clots can block the coronary arteries and cause a heart attack or even death.
The Interaction of Coronary Heart Disease, High Blood Pressure, and Diabetes
Each of these risk factors alone can damage the heart. CHD reduces the flow of oxygen-rich blood to your heart muscle. High blood pressure and diabetes may cause harmful changes in the structure and function of the heart.
Having CHD, high blood pressure, and diabetes is even more harmful to the heart. Together, these conditions can severely damage the heart muscle. As a result, the heart has to work harder than normal. Over time, the heart weakens and isn’t able to pump enough blood to meet the body’s needs. This condition is called heart failure.
As the heart weakens, the body may release proteins and other substances into the blood. These proteins and substances also can harm the heart and worsen heart failure.
People who have type 1 or type 2 diabetes are at risk for diabetic heart disease (DHD). Diabetes affects heart disease risk in three major ways.
First, diabetes alone is a very serious risk factor for heart disease. Second, when combined with other risk factors, diabetes further raises the risk of heart disease. Third, compared with people who don't have diabetes, people who have the disease are more likely to:
- Have heart attacks and other heart and blood vessel diseases. In men, the risk is double; in women, the risk is triple.
- Have more complications after a heart attack, such as angina (chest pain or discomfort) and heart failure.
- Die from heart disease.
The higher your blood sugar level is, the higher your risk of DHD. (A higher than normal blood sugar level is a risk factor for heart disease even in people who don't have diabetes.)
Type 2 diabetes raises your risk of having “silent” heart disease—that is, heart disease with no signs or symptoms. You can even have a heart attack without feeling symptoms. Diabetes-related nerve damage that blunts heart pain may explain why symptoms aren't noticed.
Other Risk Factors
Other factors also can raise the risk of coronary heart disease (CHD) in people who have diabetes and in those who don't. You can control most of these risk factors, but some you can't.
For a more detailed discussion of these risk factors, go to the Health Topics Coronary Heart Disease Risk Factors article.
Risk Factors You Can Control
- Unhealthy blood cholesterol levels. This includes high LDL cholesterol (sometimes called "bad" cholesterol) and low HDL cholesterol (sometimes called "good" cholesterol).
- High blood pressure. Blood pressure is considered high if it stays at or above 140/90 mmHg over time. If you have diabetes or chronic kidney disease, high blood pressure is defined as 130/80 mmHg or higher. (The mmHg is millimeters of mercury—the units used to measure blood pressure.)
- Smoking. Smoking can damage and tighten blood vessels, lead to unhealthy cholesterol levels, and raise blood pressure. Smoking also can limit how much oxygen reaches the body's tissues.
- Prediabetes. This is a condition in which your blood sugar level is higher than normal, but not as high as it is in diabetes. If you have prediabetes and don't take steps to manage it, you'll likely develop type 2 diabetes within 10 years.
- Overweight or obesity. Being overweight or obese raises your risk of heart disease and heart attack. Overweight and obesity also are linked to other heart disease risk factors, such as high blood cholesterol, high blood pressure, and diabetes. Most people who have type 2 diabetes are overweight.
- Metabolic syndrome. Metabolic syndrome is the name for a group of risk factors that raises your risk of heart disease and type 2 diabetes. Metabolic syndrome also raises your risk of other health problems, such as stroke.
- Lack of physical activity. Lack of physical activity can worsen other risk factors for heart disease, such as unhealthy blood cholesterol levels, high blood pressure, diabetes, and overweight or obesity.
- Unhealthy diet. An unhealthy diet can raise your risk of heart disease. Foods that are high in saturated and trans fats, cholesterol, sodium (salt), and sugar can worsen other heart disease risk factors.
- Stress and anxiety can trigger your arteries to tighten. This can raise your blood pressure and your risk of having a heart attack. Stress also may indirectly raise your risk of heart disease if it makes you more likely to smoke or overeat foods high in fat and sugar.
Risk Factors You Can't Control
- As you get older, your risk of heart disease and heart attack rises. In men, the risk of heart disease increases after age 45. In women, the risk increases after age 55. In people who have diabetes, the risk of heart disease increases after age 40.
- Before age 55, women seem to have a lower risk of heart disease than men. After age 55, however, the risk of heart disease increases similarly in both women and men.
- Family history of early heart disease. Your risk increases if your father or a brother was diagnosed with heart disease before 55 years of age, or if your mother or a sister was diagnosed with heart disease before 65 years of age.
- Preeclampsia. This condition can develop during pregnancy. The two main signs of preeclampsia are a rise in blood pressure and excess protein in the urine. Preeclampsia is linked to an increased lifetime risk of CHD, heart attack, heart failure, and high blood pressure.
Screening and Prevention
Taking action to control risk factors can help prevent or delay heart disease in people who have diabetes and in those who don't. Your risk of heart disease increases with the number of risk factors you have.
One step you can take is to adopt a healthy lifestyle. A healthy lifestyle should be part of a lifelong approach to healthy living. A healthy lifestyle includes:
- Following a healthy diet
- Maintaining a healthy weight
- Being physically active
- Quitting smoking
- Managing stress
You also should know your family history of diabetes and heart disease. If you or someone in your family has diabetes, heart disease, or both, let your doctor know.
Your doctor may prescribe medicines to control certain risk factors, such as high blood pressure and high blood cholesterol. Take all of your medicines exactly as your doctor advises.
People who have diabetes also need good blood sugar control. Controlling your blood sugar level is good for heart health. Ask your doctor about the best ways to control your blood sugar level.
Signs, Symptoms, and Complications
Some people who have diabetic heart disease (DHD) may have no signs or symptoms of heart disease. This is called “silent” heart disease. Diabetes-related nerve damage that blunts heart pain may explain why symptoms aren't noticed.
Thus, people who have diabetes should have regular medical checkups. Tests may reveal a problem before they're aware of it. Early treatment can reduce or delay related problems.
Some people who have DHD will have some or all of the typical symptoms of heart disease. Be aware of the symptoms described below and seek medical care if you have them.
If you think you're having a heart attack, call 9–1–1 right away for emergency care. Treatment for a heart attack works best when it's given right after symptoms occur.
Coronary Heart Disease
A common symptom of coronary heart disease (CHD) is angina. Angina is chest pain or discomfort that occurs if your heart muscle doesn't get enough oxygen-rich blood.
Angina may feel like pressure or squeezing in your chest. You also may feel it in your shoulders, arms, neck, jaw, or back. Angina pain may even feel like indigestion. The pain tends to get worse with activity and go away with rest. Emotional stress also can trigger the pain.
See your doctor if you think you have angina. He or she may recommend tests to check your coronary arteries and to see whether you have CHD risk factors.
Other CHD signs and symptoms include nausea (feeling sick to your stomach), fatigue (tiredness), shortness of breath, sweating, light-headedness, and weakness.
Some people don't realize they have CHD until they have a heart attack. A heart attack occurs if a blood clot forms in a coronary artery and blocks blood flow to part of the heart muscle.
The most common heart attack symptom is chest pain or discomfort. Most heart attacks involve discomfort in the center or left side of the chest that often lasts for more than a few minutes or goes away and comes back.
The discomfort can feel like uncomfortable pressure, squeezing, fullness, or pain. The feeling can be mild or severe. Heart attack pain sometimes feels like indigestion or heartburn. Shortness of breath may occur with or before chest discomfort.
Heart attacks also can cause upper body discomfort in one or both arms, the back, neck, jaw, or upper part of the stomach. Other heart attack symptoms include nausea, vomiting, light-headedness or sudden dizziness, breaking out in a cold sweat, sleep problems, fatigue, and lack of energy.
Some heart attack symptoms are similar to angina symptoms. Angina pain usually lasts for only a few minutes and goes away with rest. Chest pain or discomfort that doesn't go away or changes from its usual pattern (for example, occurs more often or while you're resting) can be a sign of a heart attack.
If you don't know whether your chest pain is angina or a heart attack, call 9–1–1 right away for emergency care.
Not everyone who has a heart attack has typical symptoms. If you've already had a heart attack, your symptoms may not be the same for another one. Also, diabetes-related nerve damage can interfere with pain signals in the body. As a result, some people who have diabetes may have heart attacks without symptoms.
The most common symptoms of heart failure are shortness of breath or trouble breathing, fatigue, and swelling in the ankles, feet, legs, abdomen, and veins in your neck. As the heart weakens, heart failure symptoms worsen.
People who have heart failure can live longer and more active lives if the condition is diagnosed early and they follow their treatment plans. If you have any form of DHD, talk with your doctor about your risk of heart failure.