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Quick Facts

Complications of Diabetes


The Manual's Editorial Staff

Last full review/revision May 2021| Content last modified May 2021
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Diabetes is a disease in which your blood sugar (glucose) levels are too high.

You get diabetes if your body's normal way of controlling blood sugar isn't working right.

What are complications of diabetes?

Complications are health problems that happen as a result of having a disease. Diabetes damages the blood vessels that supply oxygen and nourishment to your organs. So people with diabetes may have many serious long-term complications.

  • Complications can include stroke, blindness, heart attack, kidney failure, skin sores, and numbness in your feet

  • Complications may start within months or take years to start—most get worse over time

  • You can lower your chance of diabetes complications by controlling your blood sugar carefully

What causes diabetes complications?

People with diabetes have complications because not enough blood flows to certain parts of their body. Diabetes causes blood vessels to get more narrow over time. Blood can’t flow easily through narrowed blood vessels or reach certain areas.

Blood vessels narrow because:

  • Sugar-based substances build up in the walls of small blood vessels, making them thicken and leak

  • Clumps of fat build up in larger blood vessels, blocking the flow of blood (atherosclerosis)

What types of complications happen with diabetes?

Narrowed blood vessels and poor circulation of your blood can cause problems all over your body. The complications depend on which organ is affected. You may have one complication or many:

  • Heart: Chest pain, heart attack

  • Brain: Stroke

  • Legs: Cramps when walking

  • Eyes: Decreased vision and sometimes blindness

  • Kidneys: Kidney failure

  • Nerves: Tingling, burning pain, or numbness in you legs and feet

  • Skin: Skin sores (ulcers), infections, or slow healing wounds, particularly on your feet

Poor blood circulation to the legs can cause you to need an amputation of your foot or part of your leg.

How do doctors prevent complications from diabetes?

Doctors will:

  • Help you keep your blood sugar under control

  • Check you frequently for the first sign of complications

  • Have you do things to prevent complications

How do I keep my blood sugar under control?

You should:

How do doctors check for complications of diabetes?

They will do tests about once a year to check for complications, including:

  • Foot exam to test for loss of sensation and look for signs of poor circulation, such as sores that aren't healing well

  • Eye exam by an eye doctor

  • Urine and blood tests of kidney function

  • Blood tests for cholesterol levels

  • Sometimes an electrocardiogram (ECG)

How can I prevent complications of diabetes?

You can prevent or delay complications by:

  • Getting treated for problems such as high blood pressure or high cholesterol

  • Getting regular dental cleanings and checkups

  • Taking good care of your feet—wear shoes that fit well, use moisturizer, and check for injuries every day


Strictly controlling your blood sugar lowers the chance of diabetes complications. But your blood sugar level may drop too low. Low blood sugar is called hypoglycemia. Blood sugar is your body's main source of fuel, so low blood sugar can cause serious problems:

  • Hunger, sweating, shakiness, weakness, and trouble thinking clearly

  • Passing out if your blood sugar goes too low

  • Sometimes, brain damage if the hypoglycemia isn't treated quickly

Hypoglycemia is a medical emergency and needs treatment right away. To treat hypoglycemia:

  • Eat or drink something with sugar (like juice or candy) right away to raise your blood sugar level

  • If you often have low blood sugar, doctors may need to make changes in your medicines

  • In more serious cases, doctors may need to inject either glucose into your vein or a medicine called glucagon into your muscle

NOTE: This is the Consumer Version. DOCTORS: Click here for the Professional Version
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