Diabetes

What is it?

Diabetes is a lifelong condition that causes a person's blood glucose level to become too high because of problems with the hormone insulin. Glucose is the main type of sugar that the body uses for energy.

Increasing numbers of people are developing the condition which, if untreated, can lead to serious health complications – including kidney damage.

Around 40 per cent of people with diabetes could eventually develop diabetic kidney disease, which is also known as diabetic nephropathy.

It is now the leading cause of kidney failure in the UK – with around 20 per cent of people starting dialysis in the UK having the condition. This figure is expected to double in the next few years.

Types of diabetes

There are two main types of diabetes:

Type 1 diabetes – where the body's immune system attacks and destroys the cells that produce insulin. About 10 per cent of people with diabetes in the UK have Type 1 diabetes and need regular insulin injections to stay alive. It often begins in childhood or adolescence and is not caused by dietary or lifestyle factors.
Type 2 diabetes – where the body doesn't produce enough insulin, or the body's cells become resistant to insulin. This is by far the most common type of diabetes. The main risk factors for type 2 diabetes are:
- Being overweight or obese
- Sedentary lifestyle (lack of regular aerobic exercise)
- Having a family history of type 2 diabetes
- Being from a minority ethnic group
- Older age – although type 2 diabetes is now increasingly common in younger people with obesity.

Type 2 diabetes can usually be controlled with drugs and by diet to start with, but as the condition progresses with time, insulin treatment often becomes necessary to control blood glucose.

How does diabetes affect the kidneys?

High blood glucose levels increase the pressure inside the delicate filtering system in the kidney (the glomeruli), causing increasing damage to the filters. This damage causes high blood pressure, leakage of protein into the urine, and (in the long run) progressive kidney damage and eventual kidney failure. If damage is severe, the kidneys can eventually lose the ability to filter out waste products from the bloodstream, resulting in a person needing dialysis or a kidney transplant in order to stay alive.

In type 1 diabetes, it can take 10 years or more for diabetic kidney disease to develop. However, in older people with type 2 diabetes, whose kidneys may already have been damaged by high blood pressure or cardiovascular disease, diabetes appears to cause progressive kidney damage much sooner. Therefore, it is important that your doctor monitors your kidney health and that you try to look after your kidneys.

Risk factors

Some things are known to increase the risk of getting diabetic kidney disease:

Poor blood glucose control
High blood pressure
A family history of kidney disease or high blood pressure
Smoking
Developing diabetes in your teens
Being overweight or obese
Being male
Being of Afro-Caribbean or South Asian descent

Other potential complications of diabetes

High blood pressure: This is usually an early sign of diabetic kidney disease.
Arterial damage: Large blood vessels (e.g. arteries) can be damaged by diabetes, leading to a greater risk of heart attacks, strokes and cardiovascular problems – especially if high cholesterol and high blood pressure is also an issue.
Eye damage: Damage to smaller blood vessels can affect the retina at the back of the eye and cause bleeding and possible vision loss.
Nerve damage: This can cause numbness and tingling, especially in the feet.

Treatments

People can reduce their risk of developing diabetic complications by:

Giving up smoking – to benefit the kidneys, as well as the cardiovascular system and general health.
Reducing blood pressure by taking regular exercise, losing weight, keeping alcohol intake down, eating a good healthy diet, reducing salt intake and controlling cholesterol. Some people may also need to take tablets to control blood pressure. People who already have early signs of diabetic kidney disease can benefit from drugs called ACE inhibitors or ARBs.
Controlling glucose levels with the help of tablets, insulin and a healthy diet. Some new treatments that were designed to help control blood glucose appear to reduce the risk of developing or worsening diabetic kidney disease, over and above their effect on blood glucose.
Using ACE inhibitors and ARBs on a long-term basis can sometimes reduce or even ‘cure’ protein leaks and prevent further kidney damage.

Treatments for kidney failure

Dialysis and kidney transplantation can be used to treat kidney failure caused by diabetes, but potential problems can occur because diabetes can affect so many other organs, and large arteries.

Some people may also consider having a pancreas transplant to maintain better diabetic control. But this is a bigger operation and carries more risks than a kidney transplant. Pancreas islet cell transplantation is an alternative that is suitable for some people.

Help for you

If you have diabetes, your doctor should be monitoring your kidney health. This is normally done at least annually, with a blood and urine test to check how well your kidneys are working.

Further information is available from:

You can also watch GP Dr Kathryn Griffith (who specialises in kidney health) explain the link between diabetes and kidney disease.

If you have any queries or concerns, talk to your diabetes care team, who should be able to answer most of your questions.

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The need for more research

Much more research is urgently needed to work out how to prevent so many people with diabetes developing kidney damage, and slowing its progression once kidney damage has set in.
We’re working with Diabetes UK to highlight the seriousness of kidney disease in people with diabetes and to address the problem together.

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