Sandra Williams, MD and Keith Norris, MD

Diabetes is the leading cause of kidney failure in the United States. i Nearly one out of every two people treated with dialysis or a kidney transplant has diabetes. Therefore, knowing more about diabetes is important for people with kidney disease. Diabetes does not only affect the kidneys. Diabetes can affect the entire body.

First, what is diabetes?

According to the World Health Organization, diabetes is when the body has a problem handling sugar. Normally the body handles sugar by making a hormone called insulin. Diabetes causes the body to not make enough insulin, or the insulin is not working well. Sometimes both problems occur together. (Insulin is a hormone your body needs to handle sugar well.) When your body makes enough insulin, and the insulin is working well, muscles and tissues take up sugar from the blood to use as energy. When the body does not make enough insulin or the insulin is not working well, then any sugar eaten cannot be taken up by the tissues. The sugar stays in the blood and this causes the blood sugar level to be high. This is the first sign that diabetes has started. If the high blood sugar level is not fixed, then after several years, many organs in the body will be harmed. Figure 1 shows the number of people with diabetes in certain parts of the world. Each year more and more people around the world get diabetes. Right now in the United States more than 30 million people may have diabetes.

Are there different types of diabetes?

Yes. There are two main types of diabetes. They are called type 1 diabetes and type 2diabetes.

Type 1 diabetes:

Only one of every 10 people with diabetes has type 1 diabetes. In type 1 diabetes, the body does not make enough insulin. If there is not enough insulin in the body, then the sugar builds up in the blood and the blood sugar level becomes high. A person with type 1 diabetes will often lose weight since the energy from food cannot get into the tissues. They will get weak because of low energy. If the blood sugar levels become extremely high, they will urinate more, become more thirsty and have blurry vision. Type 1diabetes usually begins at a young age. This type of diabetes is always treated with insulin, diabetes education and watching the diet. Sometimes newer medicines can also be used.

Type 2 diabetes:

This is by far the most common type of diabetes. Almost nine of every 10 people with diabetes have type 2 diabetes. In people with type 2 diabetes, the body makes insulin but the insulin does not work well. The body therefore tries to make more insulin to make up for this. However, after several years, the body becomes exhausted and can no longer make any more insulin. The insulin levels then will become low.

If the diabetes is diagnosed early, people with type 2 diabetes can take medicines to help their insulin work better. If the diabetes is diagnosed late, many people with type 2 diabetes will have to take insulin. Type 2 diabetes usually begins in adults, but it is becoming more common in young people. The reason for this is young people are exercising less and gaining more weight. Being overweight and not exercising are common causes of the body’s insulin not working well.

Most people with diabetes will not feel any differently. Only when the blood sugar levels are very high do they feel bad. They then will urinate more, become more thirsty and have blurry vision. People with type 2 diabetes are treated with oral or injected medicines, diabetes education, a controlled diet and physical exercise. 

How and when does diabetes affect the kidneys?

Early on in diabetes the high levels of sugar will cause more blood to go to the kidneys. The kidneys will then get large and work harder than usual. This causes the pressure in the kidneys to get high and protein will spill into the urine. If the high blood sugar can be fixed, then the kidneys can become normal again. However, if the high blood sugars are not fixed and stay high for three to five years, or more, then the kidneys could be harmed forever. The kidneys will spill small amounts of protein (microalbuminuria), and slowly loose their ability to clean poisons from the blood (known as glomerular filtration rate or GFR). This is one of the first signs of kidney disease, caused by diabetes. As the kidneys get worse, more protein leaks into the urine (proteinuria), the blood pressure starts to rise, and the GFR becomes even lower. Through blood testing, your doctor can check your GFR. As the kidneys get worse they cannot make enough of a hormone called erythropoietin or EPO. EPO is a hormone that makes red blood cells. Without EPO the red blood cell count becomes low and this is called anemia. Red blood cells carry oxygen to the cells in the body. When the red blood cell count is low a person becomes weak and may get other problems. Also, as the kidneys get worse they cannot make enough vitamin D. Vitamin D is also a hormone. Vitamin D helps to make bones strong. When the kidneys are only working at half of their normal rate, your doctor will check for low red blood cell count and low vitamin D levels. You may need treatment if your levels are low.

What things increase the chance of getting diabetes?

Anyone, anywhere, at any age can get diabetes. We now know there are certain conditions that can make people get the most common form of diabetes, type 2 diabetes. We are not yet sure about the conditions that cause type 1 diabetes.

Diabetes prevention and treatment:

The most important thing you can do to prevent and treat diabetes is diabetes education. Learning about diabetes can help a person understand the condition that increases the chance of getting diabetes and ways to prevent diabetes. It can also help you know the different ways diabetes is treated, and the tests which should be checked regularly.

It you already have diabetes then treatment is very important. Treatment includes:

• Diabetes education

• Insulin (inhaled, injected or used in a pump)

• Medicines that help your body make insulin or respond better to insulin

• Medicines that work like other hormones which also help your blood sugar

• Controlled diet, physical exercise and good general medical care

Taking care of your diabetes should include regular checkups.

Diabetes education:

Effective education should include more than just the person with diabetes. Family members, healthcare professionals, decision makers and the general public should also be involved in your learning about diabetes. Once you have learned about diabetes, you will be better able to care for yourself. This is called “empowerment.”

Hypoglycemia:

Hypoglycemia is a state of low blood sugar. This is dangerous because the brain needs sugar for energy. A person with kidney disease and diabetes is more likely to get low blood sugar. This is because as their kidneys get worse they may need less diabetes medicine. That is another reason why they have to see a doctor more often. Some of the signs of a low blood sugar are sweating, shaking and having an increased heart rate.

  What is all the fuss about Hemoglobin A1c (HbA1c)?

When the blood sugar is high, some of the extra sugar sticks to the red blood cells. This extra sugar can be measured by a test called the HbA1c. Since each red blood cell lives for 120 days, the HbA1c can tell how well someone’s blood sugar has been doing over the last few months. The extra sugar in the blood may also stick to other cells in the body, besides the red blood cell. This “stickiness” can harm many parts of the body.

The key to diabetes care: Balance

A healthy lifestyle means eating a balanced diet and doing regular exercise. This is one of the best ways to get your blood sugar back to normal. People with diabetes can lead a normal and active life if they get diabetes education and take care of their diabetes well.

Keith Norris, MD, is a faculty member in the Department of Internal Medicine and the Associate Dean for Research at Charles R. Drew University in Los Angeles. Dr. Norris is also a member of the AAKP Medical Advisory Board.

Sandra Williams, MD, is an Endocrinologist at North Broward Medical Center in Deerfield Beach , Florida .

References:

i U.S. Renal Data System, USRDS 2006 Annual Data Report: Atlas of End-Stage Renal Disease in the United States, National Institutes of Health, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, 2006.

ii King H, Aubert RE, Herman WH. Global Burden of Diabetes, 1995-2025: prevalence, numerical estimates, andprojections. Diabetes Care. 1998;21(9):1414-1431.

iii Martins D, Norris KC. Combating Diabetic Nephropathy with Drug therapy. Current Diabetes Reports 2001;1:148-156.