“Diabetic Nephropathy” – What Does It Mean?
One of the kidney’s essential functions is to filter the blood and remove harmful substances and toxins. In addition, the kidneys regulate:
Persistently high blood glucose levels gradually damage these functions, leading to the development of diabetic nephropathy. In our country, it is the most common cause of kidney failure, often resulting in the need for long-term renal replacement therapy (dialysis).
Modifiable Risk Factors for Diabetic Nephropathy
Additional Risk Factors
Kidney disease develops slowly and is initially asymptomatic, meaning affected individuals do not notice any symptoms. Regular urine and blood tests are therefore essential. The frequency and results of kidney examinations should be documented in the Diabetes Health Record.
Course of Diabetic Kidney Disease (Nephropathy)
The earliest stage of kidney damage cannot be detected even by laboratory tests. The first measurable sign of diabetic nephropathy is the excretion of very small amounts of protein in the urine (microalbuminuria). This stage is referred to as “incipient kidney damage” and is potentially reversible.
Early Detection by Measuring Microalbumin — Important Points to Consider:
If protein excretion increases to more than 300 mg per day (albuminuria), kidney damage is rarely reversible. Protein excretion above 0.5 g per day is referred to as “overt proteinuria,” and the risk of permanent kidney failure becomes high. Only in advanced stages of kidney damage does a reduction in kidney function become detectable in the blood, indicated by elevated creatinine levels.
Even in early stages of kidney disease, blood pressure rises, followed later by blood lipid levels—both major risk factors for diseases of the large blood vessels such as heart attack and stroke.
Differentiation from Other Kidney Diseases
It is very important to note that other conditions can cause kidney damage with similar clinical signs. Examples include narrowing of the renal arteries and inflammatory kidney diseases. These conditions must be clearly distinguished, as they require different treatments.
Treatment Options for Diabetic Nephropathy
Lowering blood pressure alone can improve protein excretion and is therefore one of the most important therapeutic principles. Certain blood pressure–lowering medications are used preventively in cases of persistent protein excretion even when blood pressure is normal (ACE inhibitors, AT1 receptor blockers).
Additional measures, particularly in early stages, include good blood glucose control, reduction of excessive dietary protein intake, lowering LDL cholesterol, and avoidance of nicotine.
What You Can Do to Prevent Kidney Disease in Diabetes
Treatment Goals in Diabetic Nephropathy
New Evidence from Studies
Recent studies indicate that certain blood glucose–lowering medications can significantly slow the progression of kidney disease and decline in kidney function:
The exact mechanisms behind these effects are not yet fully understood.
These findings are surprising and highly beneficial for people with diabetes and kidney damage. European and American diabetes associations therefore recommend, in their most recent guidelines, using these medications as first-line therapy in patients with impaired kidney function and renal involvement.
Special Considerations in Blood Glucose Management
In patients with reduced kidney function, some blood glucose–lowering medications must be discontinued (particularly metformin and most sulfonylureas) or may lose their glucose-lowering effectiveness (SGLT-2 inhibitors). In addition, care must be taken, as iodinated contrast agents used in imaging, many painkillers, and fever-reducing medications can further impair kidney function.
If advanced kidney damage develops, patients should be informed early—by a kidney specialist—about the options for renal replacement therapy (dialysis).
Renal Replacement Therapy (Dialysis)
During dialysis, blood is cleaned either using an artificial filter outside the body (hemodialysis) or via the body’s own peritoneum as a natural filter (peritoneal dialysis). The choice of dialysis method and the timing of treatment are usually determined during an individual consultation with a kidney specialist (nephrologist).
More detailed information about dialysis methods and additional guidance can be found in the patient guideline for people with diabetes and kidney disease published by the German Diabetes Association (DDG).