Long-term complications associated with Type 2 diabetes

We discuss some of the health problems that can affect your health in the long term if you have Type 2 diabetes.


Having Type 1 diabetes or Type 2 diabetes is a risk factor for some complications compared with people who do not have diabetes. With Type 2 diabetes, at the time of diagnosis, around 50% may already have signs of these health problems. Here, we discuss some of the health problems that can affect your health in the long term – often called ‘chronic’ complications – if you have Type 2 diabetes.

Why complications occur

In people with diabetes, over long periods, high blood sugar levels – or your blood glucose level – can cause damage to parts of your body, such as your feet and organs like your eyes, kidneys, and heart. This damage can occur over a relatively long period of time and are often referred to as ‘chronic complications of diabetes’.

Eye problems

Often referred to as diabetic retinopathy, some people with Type 2 diabetes develop complications within their eyes. Indeed, diabetes is the leading cause of preventable sight loss in the UK. Blood vessels in the eye helps keep the retina (the ‘seeing’ part of the eye) working properly. If the blood vessels become damaged, then the retina does not function as well. If blood sugar levels remain high over a long period of time, this can increase your risk of damage to the blood vessels in your eyes.

Damage caused to these blood vessels can go unnoticed for some time, and it is not easy to spot the symptoms of early damage. Hence, it is important for people with Type 2 diabetes to get their eyes checked every year. If eye complications have started to develop, a treatment plan can be put in place that will aim to minimise further damage.

As well as having regular eye screening, you should be aware of these symptoms:

  • blurred vision, especially at night
  • shapes floating in your vision (floaters)
  • sensitivity to light

If you experience any of these symptoms, then contact your healthcare team immediately, and let them know.

Heart attack and stroke

The damage that high blood sugar causes to your blood vessels can impact on how well your heart functions. Any sugar not being used by your body builds up, and this can block or damage the blood vessels that carry blood to and from the heart and the brain. When your heart does not have enough oxygen and other nutrients, it becomes damaged – and this is one cause of cardiovascular disease (CVD). If you have CVD, you are more likely to suffer from a heart attack (when the heart is starved of oxygen and nutrients) or a stroke (when the brain is starved of oxygen and nutrients). Having high cholesterol and/or high blood pressure also increases your risk of a heart attack or a stroke. It’s therefore important for people with Type 2 diabetes to be careful that they eat a healthy balanced diet and that they maintain healthy blood pressure levels. Reducing alcohol consumption in line with or lower than the government guidelines and maintaining a healthy weight are key to controlling blood pressure.

Diabetes UK has further information on CVD and stroke, including information about their research projects in this area.

Foot problems

In a similar way that high blood sugar levels can damage blood vessels in your eyes, high blood sugar levels can also affect your circulation to your feet. It may mean that you do not have a good blood supply to your feet and lower legs, which can mean that any problems that you may have with your feet, eg, cuts or sores, take longer to heal. This damage may also mean you have a loss of sensation in your feet, which means you may be more prone to damaging them. The combination of not feeling any damage to your feet, along with it taking longer for any damage to heal, results in foot problems being a serious issue for people with Type 2 diabetes.

The NHS recommends that you check your feet every day for any injuries or soreness, and your feet should be checked every year by your GP, diabetes nurse or podiatrist. Finally, if you notice any of the following, you should speak to your healthcare team urgently:

  • pain or tingling
  • blisters and cuts that you can see but don’t feel
  • numb feet.

Nerve damage

Nerve damage (also known as diabetic neuropathy) is one of the symptoms of Type 2 diabetes that can occur if the condition is not well controlled, and your blood sugar levels are high. Nerves carry messages to and from the brain throughout our bodies. Different types of nerve damage – or neuropathies – can occur depending on which nerves have been damaged:

  • Sensory neuropathy occurs when nerves involved with carrying information about touch, temperature and pain from skin, bones and muscles are damaged. Symptoms of sensory neuropathy include the inability to feel pain or changes in temperature, tingling or numbness. This is particularly an issue with feet since any injuries sustained here may not be felt and may not heal.
  • Autonomic neuropathy occurs when nerves carrying information to and from your organs and glands are affected. People with autonomic neuropathy may experience issues with bodily functions that would normally happen without thinking, for example, bowel and bladder control, heart beating, problems with sweating and, in men, impotence.
  • Motor neuropathy affects signals between the brain and muscles that focus on movement. The muscles are affected through weakness or wasting and are more prone to twitching and cramps.

Kidney disease

Although kidney disease (also known as renal impairment) can occur due to other reasons, it is common for people with Type 2 diabetes to suffer from renal impairment. In these cases, the condition is also called diabetic nephropathy. High blood sugar levels cause damage to blood vessels in the kidneys and, as a result, the kidneys do not function properly. In advanced cases, which often result after a long time with uncontrolled blood sugar levels, people may have what is called end-stage renal disease, or ESRD.

Diagnosing kidney disease can take time, since the symptoms may only appear in more advanced stages. Symptoms to look out for include:

  • Swelling of the feet and ankles, and hands
  • Dark-coloured urine (caused by the presence of blood)
  • Becoming short of breath when climbing the stairs or doing gentle exercise
  • Feeling tired
  • Feeling or being sick

By attending your annual health checks, which will include tests for kidney function, any deterioration in kidney health can be diagnosed and treated.

How to manage complications

While the list of potential Type 2 diabetes complications can be daunting, there are many ways that people can reduce their risk of developing these issues:

  • Controlling blood sugar levels is the key to reducing the risk of these complications
  • Adopt healthy lifestyle habits, such following diet and exercise advice given by your healthcare team
  • Ensure any diabetes medications are taken as prescribed
  • If you smoke, try to stop
  • Do not exceed the recommended alcohol limits
  • Attend all of your regular health appointments, including your annual eye and feet checks.

Frequently asked questions

1. How can I prevent complications of diabetes?

Several long-term complications occur due to blood sugar levels being too high for long periods of time. By controlling your blood sugar levels, you can reduce the risk of these complications. Adopting healthy lifestyle habits, such following diet and exercise advice from your healthcare team, ensuring you take your diabetes medications as prescribed, stopping smoking and not exceeding the recommended alcohol limits, will help improve your overall health and can help reduce the risk of developing severe complications.

2. How often do I need check-ups?

Type 2 diabetes check-ups help to monitor your general health, and to check on the development of some of the complications. Every 3 months, you should have your blood sugar (HbA1c) check, which is often done by your GP or diabetes nurse. During this time, they can also check your blood pressure and perform urine test, which checks the health of your heart and kidneys. Every year, you should have your feet checked, as well as your eyes.