Diabetes is a chronic disease caused by problems with the production and /or action of insulin in the body. Insulin is an important hormone that helps to move glucose (a type of sugar) from the food we eat into the body’s cells so it can be used as energy. If you have diabetes, either your pancreas does not produce the insulin you need (type 1) or your body cannot use the insulin you produce effectively (type 2). A high level of glucose  in the blood or urine is usually a clear sign of diabetes. 

Look, listen and learn about how you could be affected by diabetes - online simulation of how diabetes occurs from Diabetes Australia-NSW.  Also try The Diabetes Channel which educates via a range of videos on many different subjects.

The most common types of diabetes are:

Type 1 - can affect people of any age but is more common in young adults and children. In type 1, your body produces little or no insulin. People with Type 1 diabetes must have daily insulin injections to stay alive.

Type 2 - is most common if you are over the age of forty, particularly if you are overweight. It is strongly linked to obesity and lack of physical activity and Type 2 is now affecting children and young adults. People with Type 2 do not always need insulin. Often they can manage their diabetes by simply controlling food intake, losing weight (if necessary) and doing regular moderate physical activity.

Some important statistics to note are:

• People who are obese are up to 3.2 times more likely to develop Type 2 diabetes. Are you at risk?  Refer to the Diabetes Action Program.
• Type 2 diabetes in particular is reaching epidemic proportions globally. Australia already has one of the highest rates of diabetes in the world. Many more may have diabetes but not know it.
• By 2031 it is estimated that 3.3 million Australians will have Type 2 diabetes, and a high proportion of this number will develop kidney failure.
• People who have one parent who has Type 2 diabetes have a one in four risk of developing Type 2 diabetes. Those with both parents diagnosed are at a one in two risk.
• Diabetes is the leading cause of kidney failure, accounting for 30% of new dialysis patients. Twenty years ago Type 2 diabetes accounted for only 2% of new dialysis patients.
• Maintaining normal blood glucose levels is important in helping reduce kidney problems in people with diabetes.

Kidney Health Australia has created this webpage to highlight that diabetes is a major cause of kidney failure in Australia.  You may also wish to visit DiabetesAustralia for other information. National Diabetes Week.

• About half of people with Type 1 diabetes will develop early kidney disease. About 20% of people will develop proteinuria and gradually progress to kidney failure. Another 10% progress to kidney failure with no proteinuria. Between 10-20% die of kidney failure.

• In Type 2 diabetes chronic kidney disease is often evident at the time of diagnosis. The clinical features and pathway followed in type 2 diabetes with kidney involvement is similar to that of of Type 1 diabetes.

Diabetic Nephropathy and Chronic Kidney Disease (CKD)

Each kidney contains up to one million nephrons, the filtering units of the kidneys. Inside a nephron is a tiny set of looping blood vessels called the glomerulus. Damage to these filters caused by diabetes is called diabetic kidney disease.  It is also known as Diabetic Nephropathy (3D education video from Virtual Renal Centre WA). 

Diabetic Kidney Disease worsens diabetic complications such as nerve and eye damage as well as increasing the risk of cardiovascular (heart).  Diabetic nephropathy damages blood vessels including those in your kidney filters and if severe, can lead to kidney failure. 

• Chronic Kidney Disease
• Heart disease and Chronic Kidney Disease
• Kidney Health and blood bressure
• Proteinuria

Diabetes also affects your kidneys in other ways. Changes to the immune system that occur in diabetes make a person more vulnerable to kidney and Urinary Tract Infections (UTIs). Nerve damage can also affect your bladder making it more difficult to pass urine. Urine build up in the bladder can create a back flow into your kidneys resulting in scarring. If you have diabetes, your chance of kidney damage greatly increases if you smoke and/or have high blood pressure, high cholesterol or proteinuria. It is also affected by: 

• Family history and genetic factors.  Some studies suggest that if there is a family history of high blood pressure or cardiovascular disease, your risk of diabetic nephropathy increases. Currently the genes for diabetic nephropathy have not been identified, but if your parent(s) have this condition then you are more likely to have it.
• Hyperglycaemia.  Hyperglycaemia or high blood sugar is a strong risk factor for developing diabetic nephropathy. It damages the small blood vessels in the kidneys, particularly to the capillaries in the kidney filters. Control of blood sugar levels may slow down the development of diabetic nephropathy. If you have diabetic nephropathy, regular monitoring of your blood sugar levels is very important. You may need adjustments to your diabetic medication as insulin is excreted via the kidneys. Good control of blood sugar levels and blood pressure can reduce or in some cases prevent further kidney damage.

What are the signs of diabetic kidney disease?

Diabetes is the leading cause of kidney disease in Australia.  It is also the leading cause of kidney failure in the developed world with around 35% to 40% of new cases diagnosed each year. Unfortunately diabetic kidney disease often has no symptoms or signs until it is well advanced. Some signs of reduced kidney function include:

• Increasing amounts of albumin (or protein) in the urine.  A slightly raised level of the protein ‘albumin’ in the urine (albuminuria) is an early warning sign. As the filters thicken, larger amounts of albumin and other proteins are lost (proteinuria).  Proteinuria can lead to problems with the body’s fluid balance and result in swelling (oedema), often in the legs, feet, face and hands.  

• Over a lifetime about 50% of people with Type 1 diabetes develop microalbuminuria.
• About one in three caucasian people with Type 2 diabetes will develop proteinuria within five years. It is more common in people of non-caucasian descent as about 50% will develop proteinuria. 

• Increased urine protein is associated with damage to other parts of the kidney causing scarring and reduced kidney function. This damage is similar for type 1 and Type 2 diabetes and can only be seen under a high-powered microscope so your doctor may speak to you about having a kidney biopsy. See Informed consent for medical tests.
  
• Rising blood pressure.  Slowly increasing protein is usually linked with a rise in blood pressure. This rise is small at first and may only be detected by taking blood pressure over 24-hours. Even small rises in blood pressure need to be treated as uncontrolled high blood pressure increases the risk of kidney damage. 

Declining kidney function. The kidney filtration rate does not usually begin to fall until diabetic kidney disease is well established. Once filtration is reduced, it tends to fall at a steady rate unless the right treatment is given in which case the kidney damage will stabilise.until diabetic kidney disease is well established.

In about one third of people with diabetes who develop kidney failure there is no protein to be found in the urine - here it is considered that vascular disease is the cause of kidney trouble.

In some cases diabetic kidney disease causes the kidney filters to become blocked and stop working, which results in kidney failure. If the filtration rate falls very low, waste and fluid build up in the blood and kidney failure symptoms develop. You can have serious kidney damage without knowing it. Kidney failure symptoms usually only occur when kidney function is less than 25% of normal. Early signs that you or your doctor might detect include:

• High blood pressure
• Changes in the amount and number of times urine is passed, eg. at night
• Changes to the appearance of urine
• Blood in the urine
• Puffiness, eg. legs and ankles
• Pain in the kidney area
• Tiredness and difficulty sleeping
• Loss of appetite
• Headaches
• Lack of concentration
• Difficulty sleeping
• Itching
• Shortness of breath
• Nausea and vomiting
• Less need for insulin or pills for your diabetes (but not in the early stages of kidney disease)

It is very important that kidney disease is detected early as appropriate treatment can help to increase the life of your kidneys.

What are the complications of diabetic kidney disease?

If you have diabetic kidney disease, the other complications of diabetes can be made worse, including:

Cardiovascular disease.  Cardiovascular disease includes all diseases and conditions of the heart and blood vessels, such as arteries and veins. The most common diseases and conditions include heart attack, heart failure, stroke and blockages in the blood vessels. The risk of cardiovascular disease is much higher in people with chronic kidney disease, particularly if they have diabetes.

Retinopathy.  This is a complication causing blindness or visual impairment. There is an increased risk of retinopathy for people with type 1 diabetes and diabetic kidney disease. This risk is not yet well understood for type 2 diabetes. Some ethnic backgrounds may put people with diabetic kidney disease at greater risk of retinopathy.

Neuropathy.  People with diabetes may be at more risk of damage to their nerve fibres (neuropathy). This can cause weakness in the arms and legs or problems in organs, e.g. digestive tract, heart and sexual organs. Neuropathy may have a role in causing damage to the kidneys.

Which factors increase the risk of diabetic kidney disease?

Some of the factors increasing the risk of diabetic kidney disease cannot be changed, including:

Duration of diabetes.  Early signs of Chronic Kidney Disease in people with diabetes is less than 10% in the first ten years and rises to between 20 – 30% over the next ten years. If diabetes is diagnosed late, urine protein may be present.

Family history and genetic factors. The genes for diabetic kidney disease have not been identified. However some studies suggest that for people with diabetes, a family history of high blood pressure or heart disease can increase the risk of diabetic kidney disease.  

Age.  A natural, slow decline is the kidneys’ ability to filter blood occurs as you get older. During adulthood, approximately 8% of kidney function appears to be lost with each decade of life.

Aboriginal and Torres Strait Islander heritage. Diabetes is more common in people of Aboriginal or Torres Strait Island descent.

Good news -  you can lower the risk of diabetic kidney disease

There are lots of things you can do, to lower your risk of diabetic nephropathy. It is important to take control of your own health. This usually means using medication as well as making healthy lifestyle choices. Your health care team can provide advice about how you can:

Control your blood sugar levels.  Hyperglycaemia or high blood sugar is a strong risk factor for kidney damage. It affects the small blood vessels in the kidneys, particularly those in the kidney filters. Controlling blood sugar levels can slow down the development of diabetic kidney disease.

Maintain healthy blood pressure. Diabetes causes high blood pressure. High blood pressure can cause kidney damage and kidney damage can cause higher blood pressure. High blood pressure can also lead to heart attacks, strokes and loss of vision if left untreated. You may have high blood pressure and feel perfectly well. In recent years, the use of an angiotensin converting enzyme (ACE) inhibitor and an angiotensin receptor blocker (ARB) has proven effective treatment for high blood pressure. These drugs lower blood pressure by widening the arteries. They also help to protect kidney function.

Control proteinuria.  Any treatment that lowers levels of protein in the urine can help to reduce the rate of progression to kidney failure. Two important drugs used to treat proteinuria are angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARB). These drugs should be used even if blood pressure is in the desired range. Reduction in salt intake to ‘low normal’ can also help to reduce proteinuria.

Control cholesterol levels.  Cholesterol is a type of fat or lipid. There are two types of cholesterol – low-density lipoprotein (LDL) or ‘bad’ cholesterol and high-density lipoprotein (HDL) or ‘good’ cholesterol. Triglycerides are a form of stored body fat. Some studies have shown that high cholesterol can increase the progression of diabetic kidney disease. It is important to control your blood cholesterol and triglyceride levels with diet and medication if necessary.

Become a non-smoker.  It is well known that smoking harms the body. Smoking causes a narrowing of the arteries, including the small vessels in the kidney filters. This reduces the kidneys’ ability to work properly. If you have diabetes and smoke, the risk of developing proteinuria is much higher. Smoking also increases blood pressure. For reasons that are not well understood, smoking appears to speed up the progression of diabetic kidney disease to kidney failure.  

Live a healthy lifestyle. The risk of type 2 diabetes can be reduced by up to 60% by adopting a healthy and active lifestyle. Some of the risk factors for developing diabetic kidney disease relate everyday choices.

Take positive steps to avoid this diagnosis:

• Ensure that your insulin levels and diabetic control is excellent.
• Be aware of and maintain good blood pressure control.
• Choose the right foods - it is important to consult a doctor or dietitian about a suitable diet.
• Be a non-smoker  (QUIT  Ring 13 78 48  ask for Quit Pack sent free of charge).
• Have your urine checked for microalbuminuria at least once a year. This test looks for tiny pieces of protein that are lost through the kidneys and shows if the kidneys are leaky.
• Have a blood test for kidney function at least once a year.
• Treat urine infections immediately.
• Maintain healthy cholesterol levels.
• Drink alcohol in moderation.
• Maintain a healthy weight.
• Maintain a positive 'stay well' attitude, do things that help you to relax and reduce stress.
• Make regular moderate physical activity a habit - keep fit.
  It makes your insulin work better and lowers your blood glucose levels.
  Control blood fats (cholesterol and triglycerides), blood pressure and body weight.
  Increases your general sense of well-being and increases bone strength.
• Ask your doctor to inform you about new developments in the treatment of diabetes.

Early detection of diabetic kidney disease can help prevent the progression to end stage kidney failure and the need for dialysis or transplantation. 

• American Diabetes Association
• Diabetic Nephropathy  Excellent 3D overview - Virtual Renal Centre WA (Aust)
• Diabetes Action  Are you at risk?  Measure yourself - find out about Diabetes 2 (Diabetes Australia)
• Diabetes Australia Web Site  Diabetes Helpline 1300 136 588
• Diabetes Australia - NSW
• Diabetes Multilingual Health Resources  (Diabetes Australia)
• Diabetes - What you need to know in other languages series available in Arabic, Chinese, Vietnamese, Greek and Italian from Diabetes Australia-NSW
• Global statistics on diabetes and kidney disease for health professionals
• International Diabetes Institute (Victoria)
• Juvenile Diabetes Foundation (USA)
• myDr.com.au - Diabetes Education Health Centre 
• National Institute of Diabetes and Digestive and Kidney Diseases (USA)  Kidney & Urological Diseases
• Online simulation of how diabetes occurs  Diabetes Australia-NSW

Are you a Health Professional or Expert Patient 

If you are a kidney health professional or 'expert patient' you will find more information of interest around the treatment of diabetes and kidney disease at our Publications for Health Professionals webpage - in particular the following publications:

• The Management of CKD in General Practice Published by Kidney Health Australia and formally endorsed by the RACGP, the ANZSN. This booklet provides a comprehensive summary of current guidelines and clincial tips to help identify, manage and refer CKD in general practice.  It is accompanied by a laminated easy to use reference card for the management of CKD which highlights key points for easy access.
  
• Type 2 Diabetes from a GPs perspective  Published by Kidney Health Australia in association with the National Evaluation of the Frequency of Renal Impairment cOexisting with NIDDM) NEFRON Study -  a collaborative effort of the Baker Institute, Kidney Health Australia, and Servier.  

Associated publications supporting this booklet are referenced below: The burden of chronic kidney disease in Australian patients with type 2 diabetes (the NEFRON study) Merlin C Thomas, Andrew J Weekes, Olivia J Broadley, Mark E Cooper and Tim H Mathew MJA • Volume 185 Number 3 • 7 August 2006

The assessment of chronic kidney disease in Australian patients with type 2 diabetes (NEFRON-2)  Merlin C Thomas, Andrew J Weekes, Olivia J Broadley, Mark E Cooper and Tim H Mathew MJA • Volume 185 Number 5 • 4 September 2006

The management of diabetes in Indigenous Australians from primary care Mark Thomas,1 Andrew J Weekes,2 and Merlin C Thomas3 1.  Dept of Nephrology, Royal Perth Hospital, Box X 2213, Perth, Australia 2.  Servier, Hawthorn, Melbourne, Australia 3.  JDRF/Danielle Alberti Memorial Centre for Diabetes Complications, Baker Medical Research Institute, Melbourne Australia BMC Public Health. 2007; 7: 303. Published online 2007 October 25. doi: 10.1186/1471-2458-7-303. PMCID: PMC2174478  Copyright © 2007 Thomas et al; licensee BioMed Central Ltd