What is diabetic kidney disease?
Diabetic kidney disease — also called diabetic nephropathy — is a serious complication of both type 1 and type 2 diabetes that affects the kidneys' ability to filter waste from the blood. It is the leading cause of chronic kidney disease and kidney failure in Australia, and one of the most significant long-term complications of diabetes.
The kidneys contain millions of tiny blood vessels that act as filters. Over time, persistently high blood glucose levels damage these vessels, gradually impairing kidney function.
The process is typically slow and silent — it can take years or even decades to develop — but the consequences can be severe if it goes undetected or unmanaged.
The encouraging news is that with good diabetes management and early intervention, the onset and progression of diabetic kidney disease can be significantly slowed — and in some cases prevented altogether.
How does diabetes damage the kidneys?
High blood glucose puts the kidney's filtering system under sustained stress. The tiny blood vessel clusters inside the kidneys — called glomeruli — become thickened and scarred over time. As damage accumulates, the kidneys become progressively less able to do their job, allowing waste products to build up in the blood and useful proteins to leak into the urine.
High blood pressure, which is both a cause and a consequence of kidney damage, accelerates this process considerably. This is why managing blood pressure is just as important as managing blood glucose in protecting kidney health.
What are the symptoms?
In the early stages, diabetic kidney disease has no symptoms at all. This is what makes regular screening so important — by the time symptoms appear, significant damage has usually already occurred.
As the condition progresses, symptoms may include swelling in the feet, ankles or legs (caused by fluid retention as the kidneys lose their ability to regulate fluid balance), fatigue, nausea, poor appetite, difficulty concentrating and changes in how often you need to urinate.
How is it detected?
Diabetic kidney disease is detected through two routine tests that should be part of every person's annual diabetes review. A urine test checks for albumin — a protein that healthy kidneys keep in the blood but damaged kidneys allow to leak into the urine. A blood test measures eGFR (estimated glomerular filtration rate), which indicates how well the kidneys are filtering.
If you have diabetes, these tests should be performed at least once a year. Early detection is one of the most powerful tools available.
How is it managed and treated?
Management focuses on slowing or halting the progression of kidney damage. The key strategies include keeping blood glucose as close to target as possible, controlling blood pressure rigorously (target levels are typically lower for people with kidney disease than for the general population) and not smoking.
Several medications have been shown to directly protect the kidneys in people with diabetes, independently of their effects on blood glucose or blood pressure. SGLT2 inhibitors and GLP-1 receptor agonists — both relatively new classes of diabetes medication — have strong evidence for kidney protection and are now recommended as first-line treatment for many people with type 2 diabetes and kidney involvement. ACE inhibitors and ARBs (angiotensin receptor blockers) also have an important role in protecting kidney function.
For people whose kidney disease progresses to kidney failure, treatment options include dialysis and kidney transplantation.