When you have type 2 diabetes the focus is often on controlling your blood sugar (glucose) levels. This might be through diet and exercise, other lifestyle changes, or it may mean starting medication. However, it is not uncommon for someone newly diagnosed with type 2 diabetes to have had this condition for many months or years prior to the actual diagnosis. For this reason, your doctor or diabetes nurse will arrange for you to have an eye check to screen for any diabetes related changes. You should also have your urine checked to see if the kidneys are working normally.

Your kidneys essentially filter your blood, eliminating toxins and waste but also actively reabsorbing essential minerals and glucose filtered from the blood. However, the kidneys are much more than just filters for the blood, they also monitor and maintain the water balance in the body and therefore also have an important role in controlling blood pressure. The kidneys help balance the acid level of the blood and can stimulate the production of red blood cells and maintains the blood levels of many essential minerals such as sodium, potassium, calcium, phosphate, etc.

The intricate architecture of the kidney’s filtering mechanism allows it to work as a very selective filter so usually only the fluid component of the blood is removed and there are few, if any blood cells or blood proteins in urine. In diabetes the filtering mechanism can become disrupted and less selective, allowing small amounts of protein to leak from the blood into the urine. Most people with type 2 diabetes will have a laboratory urine test to check for this protein leak at least once a year.

What can you do to prevent Diabetic Kidney Disease?

Around 40% of people with type 2 diabetes will develop diabetic kidney disease. Type 2 diabetes is the most common reason for people to require renal dialysis. This is where a machine filters the blood because the kidneys are no longer able to function well enough to prevent toxins building up in the body.

Some things that we cannot change make us more likely to develop diabetic kidney disease. Like being older, being a bloke and our ethnicity. As part of the aging process, we steadily lose a small amount of the filtering capacity of our kidneys. People of Māori descent have a 6 times increased risk of kidney failure due to type 2 diabetes compared to Pākehā. Pacifica people have twice the risk again of diabetic kidney disease as Māori. The duration that you have had diabetes and any coexisting kidney conditions are also important risk factors.

However, there are many ways that you can reduce your risk of diabetic kidney disease. It is well understood that good control of your blood glucose can help delay or even prevent diabetic kidney disease. Early intensive control of blood sugars, prior to developing kidney disease, can reduce the risk by around a third. Importantly, the glucose target that is best for you should be discussed with your doctor or diabetes nurse. It will depend upon many factors, including how long you have had diabetes, your age and the risk from more intensive blood sugar control, such as “hypos” or low blood sugars. How well you control your blood glucose is more important than what treatments are needed to control it. For instance, someone taking tablets to achieve excellent control is going to reduce their risk of diabetic kidney disease more than someone using diet alone who is running high blood sugars.

The second important factor in reducing your risk of diabetic kidney disease is good blood pressure control. When first diagnosed with type 2 diabetes, most people will also be started on blood pressure medication. This is because the target for treating high blood pressure is lower if you have type 2 diabetes. Anyone with a blood pressure that is persistently 130/80 or higher is likely to have been prescribed a blood pressure medication called an ACE inhibitor, the so called ‘prils’ (e.g. Accupril/quinapril, enalapril etc.), or other similar medication. These medications protect the kidneys by lowering your blood pressure and reduce the pressure within the kidney’s delicate filter mechanism. It is very common in type 2 diabetes to need more than one medication to adequately control blood pressure. Additionally, managing blood cholesterol levels and avoiding any medications that can damage the kidneys, and in those people with established kidney disease, control of how much protein is eaten are also helpful measures.

Future Developments

In New Zealand, the funding to allow better access to newer classes of diabetic medications is finally on the horizon. One medication, and it is a bit of a mouthful – Empagliflozen, is a new class of drug that help control diabetes by reducing glucose that has been filtered out the blood by the kidneys from being returned to the body. This class of drug has also been shown to improve diabetes control, lower blood pressure and delay the progression of diabetic kidney disease. Another medication, Dulaglutide, which works like one of the hormones in your gut can also slow the progression of kidney disease. The treatment of type 2 diabetes is also rapidly progressing with much attention now being focused on several novel dual acting agents that are under study in clinical trials around the world. It is hoped that in addition to providing more effective ways to control blood sugars, these new treatments may also provide protection to the heart and kidneys.