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Complications of Type 2 Diabetes and Reducing Your Risk of Developing Complications

  • Amy Scholten, MPH
Publication Type:

Condition InDepth

Complications of Type 2 Diabetes and Reducing Your Risk of Developing Complications

Possible Complications

Abnormal blood glucose (sugar) levels can lead to problems. These include the following:


Hypoglycemia is more common in people who take insulin. It can also occur in people who take oral (by mouth) medicine. Hypoglycemia can be caused by:

  • Taking too much insulin or oral diabetes medicine
  • Skipping or delaying a meal, or eating a smaller meal than usual
  • Exercising harder or longer than usual


Hypoglycemia can be managed by knowing symptoms and treating them right away. The symptoms include:

  • Shakiness
  • Lightheadedness or fainting
  • Sweating
  • Hunger
  • Headache
  • Pale skin color
  • Sudden moodiness or behavior change
  • Clumsy or jerky movements
  • Confusion or difficulty paying attention
  • Tingling sensations around the mouth
  • Seizures
  • Loss of consciousness

A blood glucose monitor can check for hypoglycemia. It should be treated if the glucose level is below the range the doctor said was safe. Even if a person has symptoms, it is best to use the glucose monitor. That way, they can be sure their symptoms are really due to hypoglycemia.

Safety ranges for glucose levels vary from person to person. The ranges are based on age and health conditions.


Hypoglycemia needs to be treated right away. The goal is to quickly raise blood glucose level to the person's safe range. Some ways to do this are eating or drinking some form of sugar, such as:

  • 4 ounces (118 milliliters) fruit juice or regular soda
  • 2 tablespoons raisins
  • 4 or 5 saltine crackers
  • 4 teaspoons sugar
  • 1 tablespoon honey or corn syrup

The person should always have some type of sugar with them. They should wait 15 minutes after eating, and then retest glucose level. If it is still too low, the treatment should be repeated. A person who passes out from hypoglycemia needs emergency treatment. At the hospital, the doctor may inject a hormone called glucagon. The doctor may also give a prescription for glucagon—for those at risk of hypoglycemia.

A person who has hypoglycemia should talk to their doctor.


Long-term hyperglycemia is the major cause of many diabetes problems. Hyperglycemia happens if there is no insulin to remove the glucose in blood. It can also happen when the body does not use insulin properly. It can be caused by:

  • Taking too little insulin or oral medicine
  • Eating a larger meal than usual
  • Stress from an illness or from daily life


Hyperglycemia should be treated right away. This will help to avoid further problems. The symptoms include:

  • Frequent urination (peeing)
  • Increased thirst
  • Blurred vision
  • Unexplained weight loss

If not treated, hyperglycemia can lead to life-threatening ketoacidosis. This condition happens when there is not enough sugar in the cells for energy. The body starts breaking down stored fat for energy instead. Acids called ketones the build up in the blood and cause ketoacidosis. The condition is more common in type 1 diabetes, but it may occur rarely in type 2 diabetes.

Hyperosmolar Nonketotic Coma

Hyperosmolar nonketotic coma is a life-threatening problem. It happens with hyperosmolar hyperglycemic nonketotic syndrome (HHNS). In HHNS, the body tries to get rid of excess blood glucose by passing it through urine. In severe cases, seizures, coma, and death may occur.


The symptoms include:

  • Very high blood glucose
  • Dry mouth and thirst
  • Warm, dry skin
  • Lack of sweating
  • Fever
  • Leg cramps
  • Sleepiness
  • Confusion
  • Vision loss
  • Seeing, thinking, or hearing things that are not real
  • Weakness or strange movements on one side of the body—with or without seizures
  • Frequent urination (peeing)

A person with this condition should seek medical care right away.


Long term high blood glucose levels and high blood pressure can affect the eyes. They can damage tiny blood vessels in the retina. This damage is called diabetic retinopathy.

Cataracts and glaucoma are common eye conditions. They occur more often and at a younger age in people with type 2 diabetes. Signs of eye damage include:

  • Blurry or double vision
  • Halos, flashing lights, or black spots
  • Dark or floating spots
  • Pain or pressure in one or both eyes
  • Trouble seeing things

Some people do not have symptoms until there is a lot of damage. It is important to see the eye doctor regularly. Diabetic retinopathy can be treated with laser therapy or surgery. Quitting smoking and controlling blood pressure is also important.

Kidney Disease

Between 20% to 40% of people with diabetes develop a types of kidney damage. This is called diabetic nephropathy.

High blood glucose levels and high blood pressure damage the kidney's small blood vessels. Over time, this damage can progress to kidney failure. The person may need dialysis or a kidney transplant .

Heart Disease and Stroke

Heart disease and strokes are more common in people with diabetes. The most common form of heart disease is coronary artery disease (CAD). This is blockage of the arteries to the heart muscles. This condition can lead to:

  • Chest pain (angina)—Chest pain or pressure often spreads to the arms (especially the left). Pain may happen with exercise or after eating a large meal. It may get better with rest.
  • Cardiomyopathy—This is a general weakening of the heart muscle. It is caused by narrowed, small blood vessels reducing blood flow through the heart. It can get worse and cause heart failure .
  • Heart attack—This is caused by a blood vessel blockage in or near the heart. As a result, part of the heart muscle does not get enough oxygen and nutrients. It stops working and dies. Symptoms of a heart attack include chest pain or pressure, nausea, indigestion, extreme weakness, and sweating.

A stroke can also happen if blood cannot reach the brain. This may be due to a blockage in a blood vessel. Symptoms of a stroke include:

  • Sudden weakness or numbness of your face, arm, or leg on 1 side of the body
  • Sudden drooping on one side of the face
  • Sudden confusion, trouble talking, or trouble understanding
  • Sudden lightheadedness, loss of balance, or problems walking
  • Sudden problems seeing in one or both eyes or sudden double vision
  • Sudden severe headache

Nerve Disorders

Diabetes can also cause mild-to-severe nerve damage, called diabetic neuropathy. This happens due to long term high blood glucose levels. It damages blood vessels that bring oxygen to nerves. Symptoms range from pain or tingling, to numbness and loss of feeling.

Damage to nerves can lead to repeat injuries, poor blood flow, and poor healing. This raises the risk of foot infections that are often hard to treat. When severe, blood flow is poor and the infection persists. The foot or legmay then need to be removed.

Other problems from nerve damage may include:

Foot Ulcers

Type 2 diabetes can lead to foot problems. Damage to the nerves can make it hard to feel pain, heat, and cold.

Type 2 diabetes can also cause a decrease in blood flow. This means a person with a blister or foot sore might not feel it. This can lead to the foot being re-injured. It is important to check and wash feet daily.


Long term health conditions can affect mood. Depression can make it harder to manage diabetes and related problems. A person needs to be alert for signs of depression that last at least 2 weeks. They may include sadness, hopelessness, and loss of interest in favorite activities. It is important to contact the doctor. Depression can be treated.

Lowering the Risk of Problems from Diabetes

These steps can help promote health:

  • Having regular checkups even if feeling well. The doctor can often spot early signs of problems.
  • Checking blood sugars closely and keeping them at healthy levels.
  • Following a healthful diet, with plenty of omega-3 fatty acids.
  • Not skipping meals.
  • Taking medicines (pills and/or insulin) as prescribed by the doctor.
  • Not smoking. Those who smoke should talk with the doctor about quitting.
  • Getting advised vaccines, such as: flu and pneumonia.
  • Doing regular physical activity and exercise.
  • Reaching and keeping a healthy weight.
  • Telling the doctor about any possible problems from diabetes.
  • Keeping track of moods. Being alert for lasting depressive symptoms.


Closely following a care plan can help prevent and treat problems due to diabetes. Sometimes this may include taking medicines, such as:

  • ACE inhibitors or other medicines—for high blood pressure
  • Lipid-lowering medicines
  • Other medicines, as advised


  • American Diabetes Association. American Diabetes Association; Professional Practice Committee: Standards of medical care in diabetes—2022. Diabetes Care. 2022;45 (Supplement_1): S3.
  • Diabetes mellitus type 2. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/diabetes-mellitus-type-2-in-adults.
  • Cardiovascular disease. American Diabetes Association website. Available at: https://diabetes.org/diabetes/cardiovascular-disease.
  • Hyperosmolar hyperglycemic nonketotic syndrome. Cleveland Clinic website. Available at: https://my.clevelandclinic.org/health/diseases/21147-hyperosmolar-hyperglycemic-syndrome
  • Hyperglycemic hyperosmolar state in adults. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/hyperglycemic-hyperosmolar-state-in-adults.
  • Hypoglycemia in diabetes. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/hypoglycemia-in-diabetes.
  • 9/11/2014 DynaMed Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Tovote KA, Fleer J, Snippe E, et al. Individual mindfulness-based cognitive therapy and cognitive behavior therapy for treating depressive symptoms in patients with diabetes: results of a randomized controlled trial. Deabetes Care. 2014;37(9):2427-2734.
  • 12/15/2014 DynaMed Systematic Literature Surveillance http://www.ebscohost.com/dynamed: Rawlings AM, Sharrett AR, Schneider AL, et al. Diabetes in midlife and cognitive change over 20 years: a cohort study. Ann Intern Med. 2014;161(11):785-793.


  • Mark Arredondo, MD
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.