Complications of diabetes

It is most important to realize if diabetes is not treated correctly, it can seriously affect your body. The first thing to remember is you can treat many of the possible problems from diabetes. Unquestionably treatment is most effective when complications are picked up early. Therefore attending regular checkups is vital.

Two types of complications can occur. Firstly, short-term complications (also known as acute) that occur rapidly in the body e.g. hypoglycemia. Secondly, long-term complications (also known as chronic) that take time to develop due to uncontrolled diabetes. Extensive studies in the US (the Diabetes Control and Complications Trial) have shown that any improvement in blood glucose control will reduce your risk of developing complications. For that reason we want you to understand what these complications are and how to avoid them. Read our following guide to the most common complications of diabetes and how to prevent them.

What are the complications of diabetes?


In simple terms, hypoglycemia is low blood sugar (blood glucose). You need to be particularly aware of the possibility of blood sugar levels dropping if you use insulin or take sulfonylureas, eat irregularly, exercise, and drink alcohol.

If your blood sugar levels drop too far, you will experience the following symptoms:

  • Sweating, or feeling cold and clammy
  • Dizziness
  • Blurred vision
  • Looking pale
  • Drowsiness
  • Confusion
  • Irritable, upset, or angry
  • Tingling lips
  • Lightheadedness
  • Fast heart rate
  • Hunger

You can treat the problem with a glass of orange juice, glucose tablets, or sugar cubes as soon as you notice these symptoms. It is always advisable to keep a glucagon injection with you for an emergency.

Diabetic ketoacidosis complications

Frequent and prolonged high blood sugar levels can lead to diabetic ketoacidosis. Your blood becomes acidic due to the presence of ketones. This is because your cells are starved for energy and your body begins to break down fat. Ketone bodies (byproducts of fat breakdown) then build up in your body. This causes a fruity smell on your breath and is one of the classic ways your doctor can make a diagnosis.

Early symptoms of ketoacidosis:

  • Thirst or a very dry mouth
  • Frequent urination
  • High blood glucose (blood sugar) levels
  • High levels of ketones in the urine

Then other symptoms appear:

  • Constantly feeling tired
  • Dry or flushed skin
  • Nausea, vomiting, or abdominal pain
  • Difficulty breathing
  • Unable to concentrate
  • Confusion

You can use a urine test strip to easily detect ketones. Many experts advise checking your urine for ketones when your blood glucose is more than 240 mg/dL. You need to treat diabetic ketoacidosis immediately as it is a medical emergency.

Hyperosmolar Hyperglycemic Nonketotic Syndrome (HHNS)

What is HHNS? Let us break down this condition for you.

Hyperosmolar Hyperglycemic Nonketotic Syndrome is a serious complication of diabetes where you can find yourself with the highest blood glucose levels. Hyper means ‘above normal’. Osmolar means ‘concentration’. Nonketotic means no ketones are created in the blood. HHNS does not make your blood as acidic as ketoacidosis.

You will experience symptoms of weakness, thirst, decreased mental awareness, frequent urination, and rapid pulse.

This condition is most likely to occur in the elderly if they live alone and those who are unwell. A person with HHNS will have high blood sugar levels where their body will pass excess sugar in the urine. These groups can lose large quantities of fluids through sickness and diarrhea and not replace them. When you do not rehydrate your body your blood glucose continues to rise. You become increasingly confused and less mentally aware. Eventually, you will reach a point that sends you into a coma. Just like ketoacidosis, this condition is also a medical emergency.

Diabetic kidney disease

People with diabetes tend to develop some degree of kidney damage. In the US diabetes is the leading cause of kidney failure in adults, making up half of all new cases.

The kidney’s primary function is to remove excess water and waste from the body through your urine. The small vessels that do this job form a delicate network that filters out unwanted substances. This network can be damaged by high blood sugar levels, causing substances such as protein to enter your urine. To put it another way, it is like making holes in a tea strainer allowing larger tea leaves to appear in the cup. Finding protein in your urine is an early sign of diabetic kidney damage.

The microalbuminuria test is a urine test for albumin that your doctor will carry out to detect these early signs. Albumin is a protein and if found in your urine by this test your doctors will keep an eye on you to prevent more serious kidney damage or even kidney failure from happening in the long term.

Blood vessel damage

In the body, damage to blood vessels can occur when glucose levels are high. For a diabetic, this means possible complications with your blood circulation, foot problems, and heart disease.

Diabetic neuropathy

Another system of your body that is affected by diabetes is your nervous system. Nerve disease or neuropathy is seen most often in people that have had diabetes the longest. There are various forms of diabetic neuropathy:

  • Disorders linked to sensory nerves – this is the most common for diabetics and is particularly foot-related. You are unable to feel the position of your foot, as well as not being able to feel tingling or burning. This can cause pain and infections of the feet to go unnoticed, causing potentially serious problems
  • Disorders due to loss of motor nerves – this prevents your muscles from moving e.g. if the muscles to your face are affected then you may not be able to smile
  • Disorders of automatic nerves – muscles that move without you even knowing can be affected e.g. your heart pumping blood around your body

Foot and skin problems

You need to be aware of changes to your feet and skin that arise because of your diabetes.

Neuropathy makes your feet less sensitive to pain and temperature. When the ability to feel your feet reduces you are less likely to notice problems that occur. In the early stages, people often complain of pins and needles. As this progresses you are less likely to notice accidental injuries or infections. Poor care may turn breaks in the skin or small sores into deeper skin ulcers. Large or deep skin ulcers put you at risk of gangrene or foot amputation. The best way to tackle this is:

  • Get into the habit of checking your feet daily
  • See a chiropodist for corns, calluses, and toenail cutting
  • Get medical attention immediately if you see infections or ulcers developing

Skin problems in diabetics are caused by damage to small blood vessels. Most commonly dry skin and loss of elasticity occur due to neuropathy and a poor blood supply. This also means you sweat less so your skin is not protected by sweat and natural oils that keep your skin supple. Also, fungal infections are commonly seen in people with diabetes. Fungus likes moisture and high glucose levels.

Diabetes and heart disease

Diabetes and heart disease are undoubtedly linked. You are twice as likely to have heart disease or a stroke than non-diabetics. Cardiovascular disease is the number one cause of death in people living with diabetes. For this reason, doing all you can to prevent this problem from developing is essential. Make heart-healthy choices for instance:

  • Give up smoking
  • Keep your blood pressure under control
  • Pay attention to your cholesterol levels
  • Improve your diet
  • Exercise – moderately

Diabetic eye problems

Diabetic eye problems are the leading cause of vision loss among adults aged 20-74 in the US. For this reason, you must attend regular eye tests to prevent complications associated with diabetes. Eye tests are done by opticians or specialist ophthalmologists.


The buildup of sugar in the lens of your eye makes you prone to cataracts. It makes the lens of your eye cloudy, limiting the amount of light reaching the back of your eye. It is particularly bothersome in bright light. A simple operation to replace the damaged lens can be done, usually within a day. The results are generally excellent.


Glaucoma is a build-up of pressure in your eye. High pressure can damage your optic nerve leading to gradual loss of sight. Diabetics are two times as likely to develop glaucoma than people without diabetes. Medical treatment can lower the pressure and save your eye.

Diabetic retinopathy

Both cataracts and glaucoma respond to treatment well. Diabetic retinopathy is more complicated and less treatable than the other conditions.

The retina at the back of your eye has a unique structure. The middle area allows you to see color and fine detail. The outer area picks up black and white allowing you to see in the dark. High sugar levels can damage the smaller blood vessels which supply the retina. They become weaker and small blisters can form that eventually burst, forming hard lumps. This is a sign that the blood supply to your eye is not as good as it should be. These hardened areas become yellowish in color and can last for years. This process causes your vision to become weaker.

Macular edema

Macular edema is a result of diabetic retinopathy. Fluid from your retina flows into the central structure of your eye (macular) by the process described above. This causes swelling of your eye and loss of vision. Laser treatment could be an option for diabetic retinopathy but has not been so successful for macular edema.

Diabetes and oral health

People with diabetes have a high risk of gum disease. If not treated it can cause your teeth to loosen or fall out. The early stages are not very noticeable. Your dentist will be the first one to point them out. Therefore regular dental checkups are essential.

Diabetes and hearing loss

Experiencing hearing problems is common for diabetics as the condition causes damage to nerves in the ear. Nerves in the inner ear can be damaged by high blood sugar and low blood sugar slows down the nerve signal from the inner ear to the brain.

Diabetes and Alzheimer’s

The risk of developing dementia may be increased by type 2 diabetes. Important research is needed into this as the full risks of developing dementia are not known.

Diabetes and depression

Dealing daily with diabetes can be challenging and people with diabetes are more likely to have depression than people without the condition. Having a mental health issue can make it harder to follow your treatment plan and take good care of yourself. If you are concerned about your mental health speak to your doctor. There is help available.

Gestational diabetes complications

A whole new group of important considerations arises during pregnancy. Gestational diabetes is a type of diabetes first seen in pregnancy for a woman who did not have diabetes before pregnancy. If you already have pre-gestational diabetes or develop gestational diabetes you will need to be aware of how to keep yourself and your baby healthy. To begin with, you should aim to be in the best possible health possible before conceiving. Equally important, your blood glucose level should be under control. In the long run, this will lead to a much smoother pregnancy.

Complications for the baby

Gestational diabetes can bring about the following complications in your baby:

  • Excess growth
  • Type 2 diabetes later in life
  • Low blood sugar
  • Death

Complications for the mother

Gestational diabetes can lead to the following complications for the mother:

  • Preeclampsia – high blood pressure during pregnancy and after labor
  • Future pregnancies with gestational diabetes


You may be feeling concerned or even alarmed by the complications caused by diabetes. The good news is that by controlling your diabetes you can improve the outlook of complications enormously.

How to prevent diabetes complications

Above all, you need to commit to making changes in the long term to prevent diabetes complications. By and large, the steps you need to take are simple and basic. You need to follow a healthy eating plan, exercise regularly, and maintain a healthy body weight. It is important to keep blood glucose levels under control and take medication regularly. Also, attend your annual and regular checks with your healthcare team. It is possible for you to thrive with diabetes and not just live with it.

Complications of diabetes FAQs

What is the most common complication of diabetes?

There are several long term complications that can develop from diabetes. Heart disease is the number one cause of death in diabetics. Other chronic conditions which may develop if left without treatment include damage to nerves, retinopathy, gum disease, heart attacks, strokes, and sexual problems.

How do you feel when your blood sugar is too high?

High blood sugar is also known as hyperglycemia. Generally, there are two reasons this happens. Either your body does not have enough insulin or it cannot use the insulin it makes properly. The following symptoms occur:

  • Headaches
  • Blurred vision
  • Excessive thirst
  • Frequent urination
  • Fatigue
  • Weight loss

What are the three main diabetic emergencies?

  • Diabetic ketoacidosis – this occurs if your body is unable to produce enough insulin and starts to break down fat instead, causing ketones (blood acid build-up) to enter your bloodstream
  • Hyperosmolar Hyperglycemic Nonketotic Syndrome HHNS is typically caused by an infection or illness, resulting in rising blood sugar levels
  • Hyperglycemia without ketosis the body can reach extremely high levels of blood sugar without ketones 

At what sugar level should I go to the hospital?

The American Diabetes Association advises immediate hospital action if your blood sugar level is above 240mg/dL and ketones are present.

Is type 1 diabetes worse than type 2 diabetes?

No, neither type 1 diabetes or type 2 diabetes is worse than the other. Above all, how soon your diabetes was diagnosed, the progress of your diabetic complications, and any other medical conditions play a larger role in your diabetes.

Medically reviewed

A medical professional has reviewed this article.

Jamie Winn, PharmD
Jamie Winn, PharmD

Jamie Winn, PharmD

Medical Writer & Reviewer

Jamie Winn, PharmD

Medical Writer & Reviewer

Dr. Jamie Winn received his Doctor of Pharmacy in 2002 from the University of South Carolina College of Pharmacy, Columbia, SC. Jamie is a medical reviewer for NiceRx.

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The content on this website is intended for information purposes only. It does not constitute medical advice. The information on this website should not be relied upon and is not a substitute for professional medical advice. You should always speak to your doctor regarding the risks and benefits of any treatment.