Diabetic Kidney Disease
Diabetic kidney disease (also known as diabetic nephropathy) is kidney disease that occurs as a result of diabetes. It is the leading cause of end stage renal failure in the UK and it affects about 10% of type II diabetics (diabetes of late onset). Most people with diabetes do not develop CKD that is severe enough to progress to kidney failure and diabetic kidney disease also takes many years to develop.
Overall kidney damage rarely occurs in the first 10 years of diabetes, and usually 15 to 25 years will pass before kidney failure occurs. For people who live with diabetes for more than 25 years without any signs of kidney failure, the risk of ever developing it decreases.
How does diabetic kidney disease develop?
Diabetic kidney disease is caused by damage to the small blood vessels in the kidney. High levels of blood sugar make the kidneys overwork in their job of filtering the blood. Over time this can damage them so that they start to leak small amounts of protein (albumin) into the urine. This first stage is called microalbuminuria. The kidney's filtration function usually remains normal during this period. In some people, the filtering function of the kidneys is actually higher than normal in the first few years of their diabetes.
With time, the damage increases resulting in a larger leak of protein termed proteinuria. At this point, the kidney’s filtering function begins to drop (see section on chronic kidney disease for an explanation on how kidney function is measured). As kidney damage develops, blood pressure often rises as well.
What factors increase the chance of it developing?
A number of factors are known to increase the likelihood of developing diabetic kidney disease including:
Poor blood sugar control
High blood pressure
Having relatives with high blood pressure or kidney disease
Being of Indo-Asian or Afro-Caribbean background
What else is diabetic kidney disease associated with?
High blood pressure almost always develops and can often worsen, if pre-existing, in diabetic kidney disease. It is often the first abnormality that develops. Diabetic kidney disease is also a marker that there is disease of the blood vessels throughout the body. Most patients with diabetic kidney disease also have diabetic eye disease as this indicates damage to small blood vessels (termed microvascular disease) as well as damage to small nerves causing diabetic peripheral neuropathy and autonomic neuropathy. Large blood vessels can also be affected (macrovascular) leading to increased risks of heart attacks, strokes and peripheral vascular disease.
How do I reduce the risk of developing diabetic kidney disease?
Good blood glucose control is essential and the HbA1C levels (the average blood sugar over 3 months) should be 7%. This can prevent the development or slow the progression of diabetic kidney disease as well as the other complications of diabetes. Achieving this will involve the help of your diabetes team
Good blood pressure control is also extremely important and in patients who leak protein through the kidneys the target is less than 130/80 mmHg. This usually requires multiple tablets to achieve this alongside losing weight if you are overweight and having a low salt diet. Kidney specialists play an important role in managing high blood pressure in diabetic kidney disease and having key experience in using blood pressure lowering medications such as ACE inhibitors and angiotensin receptor antagonists. These drugs have a large evidence base documenting their beneficial effects in diabetic kidney disease.
When do I need to see a kidney specialist?
Kidney doctors usually advise on the management of patients who develop a protein leak through their kidneys and have declining kidney function. They often help with managing high blood pressure. Please see the section on chronic kidney disease for further information on referral criteria.