Diabetes Complications

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When you have diabetes, you are at risk for getting other health problems, called complications. This is especially true if your blood sugar levels stay high. Over time, high blood sugar can damage many parts of your body. It can lead to a variety of problems, including problems with your:


High blood sugar levels may cause temporary blurred vision. Blurry vision, floaters, or flashes of light may be a sign of diabetic retinopathy, which can lead to severe vision loss. Having diabetes also puts you at risk for cataracts and glaucoma.

Heart and blood vessels.

High blood sugar damages the lining of blood vessels. This is called hardening of the arteries, or atherosclerosis. It can lead to stroke, heart attack, peripheral arterial disease, or heart failure. Erection problems can be an early warning sign of blood vessel disease and may mean a higher risk of heart disease.


High blood sugar levels can damage nerves throughout your body. This damage is called diabetic neuropathy. There are different types of neuropathy. They may be caused by damage to nerves that sense things like pain or touch or that control things like your heartbeat, digestion, or blood pressure. Nerve damage can be painful, especially in the feet.

Feet and skin.

You may have less feeling in your feet. This means that you can injure your feet and not know it. Common infections from blisters, ingrown toenails, small cuts, or other problems can quickly become more serious when you have diabetes.

High blood sugar can damage tiny blood vessels in your kidneys that help filter waste from your blood. This kidney damage is called diabetic kidney disease (sometimes called diabetic nephropathy). You may not have any symptoms until the damage is severe. Then you may notice swelling in your feet or legs or all over your body.

Infections related to diabetes

High blood sugar from diabetes can affect the body's immune system. The immune system is the body's natural defense system that helps fight infections.

People with high blood sugar from diabetes can be more severely affected by common infections, such as influenza and pneumonia. They also are more likely to be infected with unusual organisms, such as Gram-negative bacteria or fungi.


You can help prevent or delay complications by keeping your blood sugar in a target range. You also need regular medical checkups to look for early signs of complications. If complications are treated early, the damage may be stopped, slowed, or possibly reversed.


Current as of: October 2, 2023

Author: Healthwise Staff
Clinical Review Board
All Healthwise education is reviewed by a team that includes physicians, nurses, advanced practitioners, registered dieticians, and other healthcare professionals.

The Health Encyclopedia contains general health information. Not all treatments or services described are covered benefits for Kaiser Permanente members or offered as services by Kaiser Permanente. For a list of covered benefits, please refer to your Evidence of Coverage or Summary Plan Description. For recommended treatments, please consult with your health care provider.