Kidney disease is a leading cause of illness and death among diabetics. In the United States, more than half of end-stage kidney disease is due to what is called diabetic nephropathy. Nephropathy simply means disease of the kidneys.

About 35 percent of patients with Type 1 diabetes develop the complication.

The incidence of diabetic nephropathy in those with Type 2 diabetes varies between populations. Among certain populations, such as the Pima Indians, the incidence rises to 60 percent of the population. New Zealand Maoris have an incidence of Type 2 diabetes of around 40 percent. Among Europeans, it can be as low as 15 percent.

What is diabetic kidney disease?

There are two distinct types of kidney disease in diabetes. These are called diffuse diabetic nephropathy, and nodular diabetic nephropathy. The terms diffuse and nodular refer to the particular way in which the kidney tissue is affected. However, the way in which the kidney disease shows itself clinically does not vary that much between the two types.

When someone is first diagnosed with diabetes, there is often already some damage to the kidneys. This causes them to be enlarged, since the rate at which they are filtering has increased by about 40 percent above normal. The next stage is the appearance of protein in the urine, at first not detectable with the dipsticks which your doctor uses in his or her surgery. Once this protein in the urine becomes detectable by normal laboratory investigations, there is a steady decline in the functioning of the kidneys. There is usually a silent phase of about ten to 15 years, in which there are no symptoms or signs of disease.

Progression of diabetic kidney disease is made worse if the person also has hypertension.

Treatment

There is no specific treatment for diabetic kidney problems. Meticulous control of blood-sugar levels has been shown to reverse the early protein leakage in some people. This may slow the progression of kidney disease.

Hypertension must be treated aggressively wherever it is present in a diabetic. The ACE inhibitors have been shown to be particularly effective in helping control kidney disease in diabetics with high blood pressure. Some recent research suggests that they may have a part to play even in patients who are not hypertensive.

Low-protein diets may be useful.

Once renal failure has started, the treatment is the same as that for any other form of kidney disease.

Chronic dialysis and kidney transplants are routine in patients with renal failure due to diabetes.