Diabetes

What is diabetes and how is it connected to chronic kidney disease?

Diabetes mellitus (DM) is a common condition, affecting around 7% of the UK population. It is the most common cause of chronic kidney disease (CKD), and is responsible for around a third of people needing kidney replacement therapy – dialysis or a pre-emptive kidney transplant.

Diabetes is a serious condition where the glucose (sugar) levels in your blood are too high. You get glucose from food and drink, and it is moved from the blood to your cells by a hormone called insulin, which is made in the pancreas. There are two main types of diabetes:

• Type 1 – usually starts in childhood or adolescence, although it can occur at any age. People with type 1 diabetes can’t make any insulin themselves as their bodies attack the cells in the pancreas that normally make it.
• Type 2 – usually starts in middle age, although it is becoming increasingly common in younger people. People with type 2 diabetes produce some insulin but it is not effective and over time not enough is made.

In both types of diabetes, because the glucose can’t get into your cells, it builds up in the blood. If left untreated, high glucose levels can cause serious damage to your body, including your eyes, heart, feet and kidneys.

Whichever type of diabetes you have, even when it is controlled, the disease can lead to kidney problems. Fortunately, most people with diabetes do not develop a kidney problem that is severe enough to progress to end-stage renal disease (ESRD), which requires haemodialysis (HD) or peritoneal dialysis (PD) or a transplant.

Diabetes can affect your kidneys in two main ways:

1. Kidney disease (diabetic nephropathy). High glucose levels cause extra blood to flow through the tiny filters in your kidneys, so they have to work harder than normal to clean it. Over time this can damage the filters, causing them to leak.
2. Disease of the kidney’s blood vessels (renovascular disease). High blood pressure causes the artery to the kidney to fur up, reducing the blood supply and causing scarring.

Kidney damage occurs slowly over many years. It can be identified in its early stages by very small amounts of protein in the urine.

This protein has leaked from the kidneys as a result of the damage to the filters. It is therefore important that people with diabetes are screened regularly for kidney disease in order to find and treat any problems early, before more serious damage can occur.

What other problems can diabetes and kidney disease cause?

Both diabetes and kidney disease can cause high blood pressure, which increases the risk of heart attacks and strokes. Foot and eye problems are also common in people with diabetes and kidney disease, but they can be prevented.

Regular checks with your GP and optician are therefore important to try to stop any problems from developing, or to spot them early on when they can be easier to treat.

How will my kidneys be monitored if I have diabetes?

Your diabetes will be monitored by your GP. It is very important to have your urine tested at least once a year, as protein leaking into the urine is the first sign of kidney damage. When it is picked up early, there are treatments that can protect your kidneys from further damage.

You will also have regular blood tests to check your kidney function. If your kidney damage progresses, you will be referred to a kidney specialist (nephrologist) at hospital to discuss treatment options.

How is diabetes treated?

Diabetes is a life-long condition that needs regular monitoring.

Type 1 diabetes is treated with multiple daily insulin injections or an insulin pump. When you are first diagnosed you will be shown how to do these injections yourself at home. You will need to continue to do these injections yourself to maintain your health. This can seem very overwhelming at first, but you will receive support from your healthcare team.

Type 2 diabetes is usually treated by making lifestyle changes, including changing your diet, increasing the amount of exercise you do and trying to lose weight if you are overweight or obese. Most people with type 2 diabetes will also be offered medication. This is usually in the form of tablets to start with, although insulin injections may also be needed eventually.

How long does it take for kidney disease to develop?

Diabetic kidney disease takes many years to develop. People who are developing kidney disease will have small amounts of a blood protein called albumin leaking into their urine. This first stage is called microalbuminuria. Kidney function usually remains normal during this period.

As the disease progresses, more albumin leaks into the urine. This stage is called proteinuria.

In time, blood pressure often rises as well. Later on, you may start to develop chronic kidney disease (CKD). At this stage, you may experience ankle swelling and shortness of breath due to fluid building up in the lungs.

It usually takes at least 10 years to get to this point, and this is when dialysis may be needed.

How do you know you have kidney disease?

People with diabetes should be screened regularly for kidney disease. The key markers for kidney disease are the levels of serum creatinine, which is used to calculate your estimated glomerular filtration rate (eGFR), and the amount of protein in your urine.

Effects of high blood pressure

In people with diabetes, both high blood pressure, called hypertension, and a family history of diabetes complications can increase your chances of developing kidney disease.

Hypertension also accelerates the progress of kidney disease when it already exists. Treating hypertension, even if it’s mild, is essential for people with diabetes.

How can I look after my kidneys if I have diabetes?

• Stop smoking if you are a smoker. Smoking is a health risk for everyone, but for people with diabetes the risk is even greater. It can make your kidney disease worse and increase the risk of heart attacks and strokes. Your doctor can help and can refer you to a stop smoking service, and you can find out more information on the NHS website.
• Keep your blood pressure under control. You should aim for a blood pressure of 130/80 or less. Your kidney team may prescribe medication to help with this. You can buy a blood pressure machine at your local pharmacy or online to check your own blood pressure at home to help keep it under control.
• Manage your cholesterol level. Try to keep it within the range recommended by your doctor or nurse. This may involve a change in diet and/or medication. Ask your kidney team to refer you to a dietitian.
• Lose weight if you are overweight. Talk to your GP about safe, healthy ways to lose weight if necessary.
• Keep active and eat a healthy balanced diet. It is recommended that everyone takes part in at least 30 minutes of moderate physical activity daily.
• Limit your alcohol intake. Try to drink no more than 14 units a week. You can find out more about alcohol and seek advice and support to reduce your intake on the NHS website.
• Take responsibility for your health. Go to all your appointments, learn the best ways to control your blood pressure and blood glucose levels and get support to take as much control of your health as possible.

Your healthcare team can help you to manage your diabetes and improve your overall health.

Treatments for kidney disease

There are treatments available for people with diabetes and kidney disease, including treatment for some of the complications.

Medication

You might need to take medication to lower your blood pressure (to 130/80, or lower), which can slow the progression of kidney disease significantly.

Two types of drugs are effective in slowing the progression of kidney disease: angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs). Patients with even slightly raised blood pressure or persistent microalbuminuria, which is the first stage of diabetic kidney disease, may be advised to take an ACE inhibitor or an ARB.

You should also aim to keep your cholesterol levels within a healthy range – usually 5.0 mmol/L or less. Some people take medication called statins to help maintain their cholesterol.

Dialysis and transplantation

When people with diabetes develop end-stage renal disease, or kidney failure, they need to have either dialysis or a kidney transplant.

Some patients with Type 1 diabetes and kidney failure can have a double kidney-pancreas transplant.

Currently, the survival of kidneys transplanted into people with diabetes is about the same as the survival of transplants in people without diabetes – on average, around 10 to 15 years). Dialysis for people with diabetes also works well in the short run.

Where can I find more information about diabetes?

You can also find out more about diabetes on the Diabetes UK and NHS websites.

Diabetes and kidney disease: download or order Kidney Care UK's information leaflet

You can download our Diabetes and kidney disease leaflet for free.

You can also order a printed copy of Kidney Care UK’s Diabetes and kidney disease leaflet to be sent to you in the post.