Topic Overview

A person is at risk for diabetes complications if blood sugar levels are often above a target range for a long period of time.

Whether complications develop also may be affected by:

• The effects of high levels of cholesterol and triglycerides.
• High blood pressure (hypertension).
• Changes in the way the blood clots.

Keeping blood sugar at a target range lowers the risk for complications.

People who have diabetes are at risk for blood vessel and nerve damage. They can develop one or several complications.

Blood vessel damage

High blood sugar causes changes in hormones and cells that can damage blood vessels or nerves, or both. Damaged blood vessels are more likely to build up plaque, increasing the risk of coronary artery disease, heart attack, and stroke. When large blood vessels are affected, complications are called macrovascular disease. Damage to small blood vessels can lead to loss of vision, kidney disease, and nerve problems throughout the body. When small blood vessels are affected, the condition is called microvascular disease.

• Blockages in the heart or brain increase the risk of heart attack or stroke. When the large blood vessels in the legs are affected (peripheral arterial disease), blood circulation to the legs and feet is reduced, causing changes in skin color, decreased sensation, poor wound healing, and leg cramps.
• Diabetic retinopathy refers to complications affecting the eyes.
• Diabetic nephropathy affects the kidneys.

Nerve damage

Nerve damage (diabetic neuropathy) can decrease or completely block the movement of nerve impulses or messages through organs, legs, arms, and other parts of the body. Nerve damage can affect your internal organs and your ability to feel pain when you are injured.

• Diabetic autonomic neuropathy occurs when nerves that control involuntary functions—such as those of the heart, digestive tract, urinary tract, and sex organs—have been damaged.
• Diabetic peripheral neuropathy occurs when the nerves that detect sensation (including pain and position) become damaged. Peripheral neuropathy usually affects longer nerves first, for example, the nerves going to the legs and feet.