Diabetes mellitus, usually called diabetes, is a disease in which your body does not make enough insulin or cannot use normal amounts of insulin properly. Insulin is a hormone that regulates the amount of sugar in your blood. A high blood sugar level can cause problems in many parts of your body.
Diabetes is the most common cause of kidney failure, accounting for nearly 45 percent of new cases. Even when diabetes is controlled, the disease can lead to nephropathy and kidney failure. Most people with diabetes do not develop nephropathy that is severe enough to cause kidney failure. About 18 million people in the United States have diabetes, and more than 150,000 people are living with kidney failure as a result of diabetes.
There are two types of Diabetes, Type I and Type 2.
Type 1 Diabetes: About 5 to 10 percent of people with diagnosed diabetes have type 1 diabetes, which tends to first occur in young adults and children. Type 1 used to be known as insulin-dependent diabetes mellitus or juvenile diabetes. In type 1 diabetes, the body stops producing insulin. People with type 1 diabetes must take daily insulin injections or use an insulin pump. They also control blood glucose levels with meal planning and physical activity. Type 1 diabetes is more likely to lead to kidney failure. Twenty to 40 percent of people with type 1 diabetes develop kidney failure by the age of 50. Some develop kidney failure before the age of 30.
Type 2 Diabetes: About 90 to 95 percent of people with diagnosed diabetes have type 2 diabetes, once known as noninsulin-dependent diabetes mellitus or adult-onset diabetes. Many people with type 2 diabetes do not respond normally to their own or to injected insulin—a condition called insulin resistance. Type 2 diabetes first occurs more often in people over the age of 40, but it can occur at any age—even during childhood. Many people with type 2 are overweight. Many also are not aware that they have the disease. Some people with type 2 control their blood glucose with meal planning and physical activity. Others must take pills that stimulate production of insulin, reduce insulin resistance, decrease the liver’s output of glucose, or slow absorption of carbohydrate from the gastrointestinal tract. Still others require injections of insulin in addition to pills.
With diabetes, the small blood vessels in the body are injured. When the blood vessels in the kidneys are injured, your kidneys cannot clean your blood properly. Your body will retain more water and salt than it should, which can result in weight gain and ankle swelling. You may have protein in your urine. Also, waste materials will build up in your blood.
Diabetes also may cause damage to nerves in your body. This can cause difficulty in emptying your bladder. The pressure resulting from your full bladder can back up and injure the kidneys. Also, if urine remains in your bladder for a long time, you can develop an infection from the rapid growth of bacteria in urine that has a high sugar level.
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.
The earliest sign of diabetic kidney disease is an increased excretion of albumin in the urine. This is present long before the usual tests done in your doctor's office show evidence of kidney disease, so it is important for you to have this test on a yearly basis. Weight gain and ankle swelling may occur. You will use the bathroom more at night. Your blood pressure may get too high. As a person with diabetes, you should have your blood, urine and blood pressure checked at least once a year. This will lead to better control of your disease and early treatment of high blood pressure and kidney disease. Maintaining control of your diabetes can lower your risk of developing severe kidney disease.
High blood pressure, or hypertension, is a major factor in the development of kidney problems in people with diabetes. Both a family history of hypertension and the presence of hypertension appear to increase chances of developing kidney disease. Hypertension also accelerates the progress of kidney disease when it already exists.
The American Diabetes Association and the National Heart, Lung, and Blood Institute recommend that people with diabetes keep their blood pressure below 130/80.
Hypertension can be seen not only as a cause of kidney disease, but also as a result of damage created by the disease. As kidney disease proceeds, physical changes in the kidneys lead to increased blood pressure. Therefore, a dangerous spiral, involving rising blood pressure and factors that raise blood pressure, occurs. Early detection and treatment of even mild hypertension are essential for people with diabetes. Drugs used to lower blood pressure (antihypertensive drugs) can slow the progression of kidney disease significantly. Two types of drugs, angiotensin-converting enzyme (ACE) inhibitors and angiotensin receptor blockers (ARBs), have proven effective in slowing the progression of kidney disease.
In people with diabetes, excessive consumption of protein may be harmful. Experts recommend that people with kidney disease of diabetes consume the recommended dietary allowance for protein, but avoid high-protein diets. For people with greatly reduced kidney function, a diet containing reduced amounts of protein may help delay the onset of kidney failure. Anyone following a reduced-protein diet should work with a dietitian to ensure adequate nutrition.
Antihypertensive drugs and low-protein diets can slow kidney disease when significant nephropathy is present. A third treatment, known as intensive management of blood glucose or glycemic control, has shown great promise for people with type 1 and type 2 diabetes, especially for those in early stages of nephropathy.