About kidney disease and diabetes

People with diabetes are more likely to get kidney disease (diabetic nephropathy), and Maori and Pacific Island people with diabetes seem to have an increased risk. Early detection of kidney disease allows for treatments to help slow damage, so see your doctor for regular kidney function checks. Kidney disease can progress to kidney failure (renal failure), which requires dialysis or organ transplantation. Measures to help lower risk of kidney problems include keeping blood pressure and blood glucose at healthy levels, and not smoking.

Home blood glucose testing improves control

In the past quite a large number of people with diabetes developed kidney disease. Now that people are able to monitor and improve their own blood glucose levels, through home blood glucose testing, it is thought a lot fewer people will develop this problem.

Recent advances in the treatment of high blood pressure in those with diabetes should cut these rates even further. Maintaining healthy blood glucose levels and a healthy blood pressure will greatly reduce your chances of developing kidney disease.

What is diabetic kidney disease?

Having diabetes can damage the small blood vessels in your body. This is particularly so if your blood glucose levels or blood pressure remain high for long periods of time.

The kidneys contain a lot of very small blood vessels. Diabetes can cause these vessels to become thickened and damaged. Eventually they become leaky, and, instead of filtering your blood properly to get rid of waste products (into your urine), they start to leak very important things such as protein out into your urine.

If this damage to the blood vessels in the kidneys gets worse, and the body isn’t able to properly get rid of its wastes, toxins begin to build up in the body and cause further damage and generalised poor health. Also see Kidney health for more about the kidneys.

Can diabetes cause other types of kidney damage?

Sometimes other problems can occur in diabetes that can make kidney disease worse. Some people with diabetes are troubled with frequent urine infections. Over time, this can worsen kidney damage. Also, some people with diabetes may develop problems emptying their bladder. This can cause a backlog pressure on the kidney and increase kidney damage.

Who is most likely to get kidney problems?

Those who are more likely to get kidney problems:

• people who have had diabetes for a long period (more than 10 years)
• people who smoke cigarettes or who have high blood pressure
• Maori and Pacific Island people seem to have more chance of getting kidney damage.

How do I avoid developing kidney disease?

There are important steps you can take to greatly reduce your chance of getting kidney problems:

• Have regular kidney function checks (see further below for details).
• Keep your blood glucose levels as healthy as possible. Every improvement, no matter how small, reduces risk to the kidneys.
• Keep your blood pressure in a healthy range (less than 130/80 mmHg is recommended by the Heart Foundation for people with diabetes).
• Have your urine checked for protein at least once a year (a urine sample is sent to a laboratory for testing).
• If you smoke try to cut down, or better still, quit. Also see: Diabetes and smoking
• Keep your blood lipids (cholesterol levels) in a healthy range.

Kidney function and related checks

You should have the following checks at least once a year. The checks will need to be done more often if you’ve had diabetes for more than 10 years, or if you are already showing signs of kidney damage. Your GP, diabetes nurse or specialist can help you get these checks done.

Blood glucose control  - This is checked by a blood test called HBA1c (glycosylated haemoglobin), which measures your average blood glucose over the past four to six weeks. To run the least possible risk of damaging your kidneys your HBA1c should be less than 7%.

Blood pressure - You should have your blood pressure checked every time you visit your doctor. The Heart Foundation recommends blood pressure stays below 130/80 for people with diabetes.

Urine protein (or microalbuminuria) - It is important to pick up protein loss from the kidneys very early so the test for protein should be a laboratory test for microscopic amounts of protein in your urine (microalbuminuria). If kidney damage is caught early enough, medication is available that can act to slow down the rate at which further damage occurs. The medications used are called ACE (angiotensin converting enzyme) inhibitors. Some people may need more than one type of medication. Once damage is advanced these medications are less effective, so the regular checks are very important. Also see: Laboratory tests for diabetes 

Blood lipids (or cholesterol) - Research is beginning to suggest the balance of fats (or lipids) in your bloodstream may affect your kidney function. Currently, a once-yearly diabetes review is free for all people with diabetes. You can arrange for your GP to tell you when it is due. All the above tests will be done as part of this. Also see: Cholesterol testing

What happens if I do get kidney disease?

If it is picked up early, there is a good chance that going on to medication (usually ACE-inhibitor) and improving your blood glucose levels will help to stop it getting worse.

If your kidney disease does get worse, it will slowly progress to what is called ‘end stage kidney (renal) failure’. This is where your kidneys can't do the job any more of filtering the waste products out of your blood. If you have this condition you may develop nausea, vomiting, weakness and fatigue.

What treatments are available for end-stage kidney failure?

There are a number of treatments available:

Haemodialysis
Haemodialysis is where you are connected to a machine that acts to cleanse your blood of waste products. If you have haemodialysis you need to connect to this machine three to four times a week for about six hours each time. Some people learn how to connect themselves and do it at home overnight while they are sleeping.

Peritoneal dialysis
Peritoneal dialysis is where you have a small tube inserted into your abdomen and you run warmed fluid into your abdomen regularly three to six times per day. This fluid acts to cleanse your blood of waste products by using a large membrane which is in your abdomen as a filter.

Kidney transplant
In a kidney transplant you are given a healthy kidney from either a dead person or a live donor with a compatible blood group and tissue type; this can be from a relative or a friend. Some surgeons are beginning to do combined kidney/pancreas transplants, but this is still very new in New Zealand and only a very limited number of people can have them.

Prevention is best option

Taking action early on in your life with diabetes can prevent you developing kidney disease. Make sure you have all your checks and do your best to stay healthy.

Related topics

Also see: Kidney health and Blood pressure and kidney disease

Original material provided by Diabetes New Zealand, 2008. Edited by everybody, June 2011.