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The complications of type 2 diabetes

The complications of type 2 diabetes

A deep dive into complications of type 2 diabetes

If you are living with type 2 diabetes, reading about a long list of things that can go wrong is not going to be fun. But it is important to understand the potential problems that could occur - that way you can identify and get help for any complications you are currently living with, or work on preventing complications that haven’t happened yet.

Most people know that diabetes is associated with high blood glucose (sugar) levels. But it might come as a surprise to learn that the main complications of type 2 diabetes aren’t directly caused by high blood glucose levels. Most complications happen when the arteries (blood vessels) supplying organs become narrowed or blocked. That is why the yearly diabetes check focuses so much on things like cholesterol, blood pressure and whether or not you smoke. All of these things contribute to arteries blocking up, so anything we can do to improve these factors reduces the risks of complications from diabetes.

The main complications of type 2 diabetes affect organs like eyes, nerves, kidneys, heart or brain. We will go through each of these below.

Eye problems (Retinopathy, cataracts and blurred vision)

Everyone with type 2 diabetes should have a yearly eye check. This eye screening will pick up any changes in the blood vessels that supply the back of your eye (retina). If these changes are identified early, they can be treated by eye specialists - protecting your vision. Before we had yearly diabetes eye checks, diabetes was one of the leading causes of blindness in the UK. The two most important things you can do to keep your eyes healthy are (1) going to your yearly eye check  and (2) keeping your average blood glucose levels (HbA1c) as well controlled as you can.

If you are having problems with blurred vision, this can be caused by high blood glucose levels or cataracts (when the lens at the front of your eye becomes cloudy), so it is worth getting checked by your doctor or optician if this is a problem for you.

Nerve problems (Pain, tingling or numbness)

If the blood supply to the small nerves in your hands or feet is reduced by diabetes, this can cause shooting pain, tingling or numbness. 

The best way to prevent damage to nerves is to try and keep your average blood glucose levels (HbA1c) as close to target as you can. Depending on your treatment, this might mean aiming for an HbA1c of 48mmol/mol (6.5%) or 58mmol/mol (7.5%).

If you have any problems with pain or tingling in your feet, it may be worth getting your B12 levels checked and speaking to your nurse or doctor. Improving your blood glucose levels may also help your symptoms - and if that doesn’t work, there are a number of different tablets that can help make your nerves less sensitive and reduce the pain or tingling.

As part of your annual diabetes check you will have a foot check to pick up any numbness in your feet. This is important to help prevent accidental damage to the skin and avoid developing foot ulcers.

Kidney problems (Chronic kidney disease - CKD)

Minor kidney damage (Chronic kidney disease stage 1-3) is very common in type 2 diabetes, and this is usually not something to worry about. The important thing is to pick up any further deterioration in your kidney function early and stop major problems developing. 

This is done by having a yearly blood and urine test as part of your annual diabetes review. If your kidney blood test drops or if your urine has protein in it - that is a sign that your kidneys need some extra protection.

The most important factor in keeping your kidneys healthy is to get your blood pressure under control (below 140/80 mmHg for most people, or below 130/80mmHg if you have any complications). It is also sensible to reduce the amount of salt you eat and avoid medication like anti-inflammatory medicines (e.g ibuprofen) which can be harmful for the kidneys if taken for too long. Certain blood pressure tablets (ACE inhibitors and ARBs) are very good at protecting the kidneys from damage.

Heart problems (chest pain or feeling very uncomfortable on exertion)

Looking after your heart and circulation is very important when living with type 2 diabetes. If the blood vessels supplying the heart become narrow, physical activity like walking fast, going up stairs or running can trigger chest pain. Typical angina is a heavy crushing pain in the middle of the chest that might spread to the left arm, shoulder or jaw. It normally settles with rest or medication for angina. 

Severe angina at rest associated with feeling sweaty or unwell might be a sign of heart attack, where one of the arteries to the heart has become completely blocked. This can be treated as an emergency in hospital by putting in a small stent that will open up the blockage.

There is a lot that can be done to reduce the risk of having angina or a heart attack. The main areas to focus on are:

  1. Good blood pressure control - regular exercise, weight loss, a low salt diet and medication will help to lower blood pressure.
  2. Lowering blood cholesterol - taking statins and a low fat diet will reduce the amount of cholesterol in the blood and reduce the chance of plaques clogging up arteries.
  3. Stopping smoking - smoking is the biggest risk factor for developing heart and lung problems and quitting will immediately start to improve your health.
  4. Good blood glucose control - it is easiest to control blood glucose levels when you are first diagnosed - and good control at the start will help reduce the risk of heart problems later in life.


Strokes and mini-strokes (TIA) are also caused by blocked arteries. Common symptoms of a stroke can include sudden onset weakness on one side of the face, weakness in one arm or leg or slurred speech. A mini-stroke may cause similar symptoms, but the symptoms may not last very long. 

Strokes and TIAs need to be seen urgently in hospital so they can be treated quickly.

Sexual problems (problems with erections and vaginal dryness)

Sexual problems can be difficult to discuss with health professionals, but they can have a big impact on someone’s life. Prescription medication can help with erection problems or vaginal dryness and it is important to be able to discuss this with your health professionals. If this is difficult to discuss in person, you might be able to email or do an online consultation that could make it easier to ask for help.

Posted by Dr Kingshuk Pal
The advice we are providing is as accurate and as comprehensive as possible, but it is only general advice and should not be used as a substitute for the individual advice you might receive from consulting your qualified medical practitioner. Please ensure you consult a qualified medical professional before making any changes to your healthcare.