If diabetes isn't treated, it can lead to a number of different health problems. 

High glucose levels can damage blood vessels, nerves and organs.

Even a mildly raised glucose level that doesn't cause any symptoms can have damaging effects in the long term.

Heart disease and stroke

If you have diabetes, you're up to five times more likely to develop coronary heart disease (CHD) or have a stroke.

Prolonged, poorly controlled blood glucose levels increase the likelihood of developing atherosclerosis (furring and narrowing of your blood vessels).

This may result in a poor blood supply to your heart, causing angina (a dull, heavy or tight pain in the chest).

It also increases the chance that a blood vessel in your heart or brain will become completely blocked, leading to a heart attack or stroke.

Nerve damage

High blood glucose levels can damage the tiny blood vessels of your nerves.

This can cause a tingling or burning pain that spreads from your fingers and toes up through your limbs. It can also cause numbness, which can lead to ulceration of the feet.

Damage to the peripheral nervous system (the nervous system outside the brain and spinal cord) is known as peripheral neuropathy.

If the nerves in your digestive system are affected, you may experience nausea, vomiting, diarrhoea or constipation.

Diabetic retinopathy

Diabetic retinopathy is where the retina, the light-sensitive layer of tissue at the back of the eye, becomes damaged.

The retina needs a constant supply of blood, which it receives through a network of tiny blood vessels. Over time, a persistently high blood sugar level can damage these blood vessels and affect your vision.

Annual eye checks are usually organised by a regional photographic unit. If significant damage is detected, you may be referred to a doctor who specialises in treating eye conditions (ophthalmologist).

The better you control your blood glucose levels, the lower your risk of developing serious eye problems.

Diabetic retinopathy can be managed using laser treatment if it's caught early enough. However, this will only preserve the sight you have rather than improve it.

Kidney disease

If the small blood vessels in your kidney become blocked and leaky, your kidneys will work less efficiently.

It's usually associated with high blood pressure, and treating this is a key part of management.

In rare, severe cases, this can lead to kidney failure. This can mean a kidney replacement, treatment with dialysis or sometimes kidney transplantation becomes necessary.

Foot problems

Damage to the nerves of the foot can mean small nicks and cuts aren't noticed and this, in combination with poor circulation, can lead to a foot ulcer.

About 1 in 10 people with diabetes get a foot ulcer, which can cause a serious infection.

If you have diabetes, look out for sores and cuts that don't heal, puffiness or swelling, and skin that feels hot to the touch. You should also have your feet examined at least once a year.

If poor circulation or nerve damage is detected, check your feet every day and report any changes to your doctor, nurse or podiatrist.

Read more about foot care and diabetes.

Sexual dysfunction

In men with diabetes, particularly those who smoke, nerve and blood vessel damage can lead to erection problems. This can usually be treated with medication.

Women with diabetes may experience:

  • a reduced sex drive (loss of libido)
  • reduced pleasure from sex
  • vaginal dryness
  • a reduced ability to orgasm
  • pain during sex

If you experience a lack of vaginal lubrication, or you find sex painful, you can use a vaginal lubricant or a water-based gel.

Miscarriage and stillbirth

Pregnant women with diabetes have an increased risk of miscarriage and stillbirth.

If your blood sugar level isn't carefully controlled immediately before and during early pregnancy, there's also an increased risk of the baby developing a serious birth defect.

Pregnant women with diabetes will usually have their antenatal check-ups in hospital or a diabetic clinic, ideally with a doctor who specialises in pregnancy care (an obstetrician).

This will allow your care team to keep a close eye on your blood glucose levels and control your insulin dosage more easily, as well as monitoring the growth and development of your baby.

Looking after your eyes

The NHS diabetic eye screening programme will arrange for you to have your eyes checked every year.

Everyone who is on a diabetes register will be given the opportunity to have a digital picture taken of the back of their eye. Speak to your GP to register.



Diabetes and eyesight

Blood vessels in the retina of your eye can bleed, become leaky or grow haphazardly. This can prevent light being detected on the retina or even reaching your retina. If left untreated, it can damage your vision. In this video, an expert explains how diabetes can affect your vision and the possible treatments for it.

Media last reviewed: 14/07/2015

Next review due: 14/07/2017

Page last reviewed: 05/09/2016

Next review due: 05/09/2018