Diabetes Day-by-Day #36 KIDNEY DISEASE Options for Prevention and Treatment Kidneys are remarkable organs. Inside them are millions of tiny blood vessels that act as filters. Their job is to remove waste products from the blood. But sometimes this filtering system breaks down. Failing kidneys lost their ability to filter out waste products. One cause of kidney failure is diabetes. -Why Diabetes Damages Kidneys- When our bodies digest the protein we eat, the process creates waste products that build up in the blood. In the kidneys, millions of tiny blood vessels (capillaries) with even tinier holes in them act as filters. As blood flows through the blood vessels, small molecules such as waste products squeeze through the holes. These waste products become part of the urine. Useful substances, such as protein and red blood cells are to big to pass through the holes in the filter. They stay where they belong--in the blood. Diabetes can damage this system. High levels of glucose make the kidneys filter too much blood. All this extra work is hard on the filters. After many years, they start to leak. Useful protein is lost in the urine. Having small amounts of protein in the urine is called microalbuminuria. Having larger amounts is called proteinuria or macroalbuminuria. In time, the stress of over work causes some filters to collapse. This collapse makes more work for the remaining filters and they, too, begin collapsing. As the capillaries lose their filtering ability, waste products start to build up the blood. Finally, the kidneys fail. This failure is called end-stage renal disease (ESRD). ESRD is very serious. A person with ESRD needs either to have a kidney transplant (tx) or to have the blood filtered by machine (dialysis). -Who Gets Kidney Disease- Not everyone with diabetes develops kidney disease. Factors that can influence development include genetics, blood glucose control, and blood pressure. The better a person keeps diabetes under control, the lower the chance of getting kidney disease. High blood pressure should also be kept under control. The healthier the blood pressure, the healthier the kidneys will be. More than 30% of people with insulin-dependent (type I) diabetes will one day have kidney disease, compared with perhaps 10% of people with type II diabetes. People with type I diabetes have 15 times the risk of ESRD as those with type II diabetes. The longer a person has diabetes, the higher the risk of kidney disease--up to a point. After 40 years with diabetes, if a person does not yet have kidney disease, he or she probably never will. Men are 50 percent more likely to get kidney disease than women. Native Americans are seven times more likely to have kidney disease than other white people. Other ethnic groups at greater risk are African Americans (three to four time the risk of whites) and Mexican Americans. Most people who get diabetic kidney disease also have diabetic eye problems. -Symptoms and Diagnosis- The kidneys work so hard to make up for the failing capillaries that kidney disease produces no symptoms until almost all function is gone. Also, the symptoms are not specific. The first symptom is often fluid buildup. Others include loss of sleep, tiredness, poor appetite, upset stomach, vomiting, weakness, and difficulty concentrating. It is vital to see a doctor regularly. The doctor can test the urine for protein, check whether blood pressure is high, and detect diabetic eye problems. -Prevention- Diabetic kidney disease can be prevented by tight blood glucose control. In the Diabetes Control and Complications Trial (DCCT), tight control reduced the risk of microalbuminuria by a third. In people who already had microalbuminuria, the risk of progressing to proteinuria was about half in people on tight control. Other studies have suggested that tight control can reverse microalbuminuria. -Treatments for Kidney Disease- When kidney disease is diagnosed early (during microalbuminuria), several treatments may keep it from getting worse. When kidney disease is caught later (during proteinuria), ESRD always follows. Treatment at this stage can only delay the inevitable. One important treatment is tight blood glucose control. Another important treatment is tight control of blood pressure. Blood pressure has a dramatic effect on the rate at which the disease progresses. Even a mild rise in blood pressure can quickly make the disease worsen. Three ways to bring blood pressure down are losing weight, eating less salt, and avoiding alcohol and tobacco. When these methods fail, certain medicines may be able to lower blood pressure. There are several kinds of blood pressure drugs. Not all are equally good for people with diabetes to take. Some raise blood glucose levels or mask some of the symptoms of low blood glucose. Those that doctors prefer for people with diabetes are called calcium-channel blockers, alpha blockers, and ACE inhibitors. ACE inhibitors may turn out to be the best drug treatment. Recent studies suggest that these drugs--which include captopril and enalapril--slow kidney disease in addition to lowering blood pressure. In fact, these drugs are helpful even in people who do not have high blood pressure. Another treatment some doctors use is a low-protein diet. Protein seems to increase how hard the kidneys must work. A low protein diet can decrease protein loss in the urine and increase protein levels in the blood. Never start a low-protein diet without talking to your doctor first. Once kidneys fail, these treatments are no longer useful. Dialysis is then necessary. The person must choose whether to continue with dialysis or to get a kidney tx. This choice should be made as a team effort. The team should include the doctor and diabetes educator, a nephrologist (kidney doctor), a kidney transplant surgeon, a social worker, and a psychologist. -Kidney Transplants- A kidney transplant, if successful, frees the person from dialysis. It makes the quality of life dramatically better. The immune system's job is to protect the body from foreign substances. As a result, the immune system will reject any organ it perceives as foreign. To reduce the chance that the immune system will reject the donated kidney, doctors prefer donors whose immune systems are similar to those of the patients. The best donor is a healthy relative. To further lower the chance of rejection, people with kidney transplants must take powerful drugs to suppress their immune systems for the rest of their lives. Having a kidney transplant is a serious matter. The operation is a major one and the drugs are dangerous with many side effects. But people who get kidney transplants are more likely to be alive after 5 years than people who stay on dialysis. -Dialysis- Dialysis is a way of cleaning the blood with an artificial kidney. Dialysis is the more common form of kidney-replacement therapy. There are two types of dialysis: hemodialysis and peritoneal dialysis. No matter which type is chosen, the person undergoing dialysis needs to work closely with the health-care team to keep diabetes under control. -Hemodialysis- In hemodialysis, an artificial kidney removes waste from the blood. To get the blood to the artificial kidney, there has to be access to the blood vessels. The place where blood is drawn is called the access connection site. Preparing this site--usually in the arm--requires surgery. The surgeon may connect a vein to an artery to make a large "vein" called a fistula or a loop. (A vein carries blood to the heart. An artery carries blood away from the heart.) Or the surgeon may implant a straight piece of tubing. The more common name for the fistula is an access. Usually, this surgery is done 2 to 3 months before dialysis is to begin so that the body has time to heal. In most cases, the surgeon puts the access in the arm not used for writing. To begin dialysis, two needles are placed in the access. One is for outgoing blood, and the other is for blood returning to the body. Blood is pumped from the arm to a dialysis machine. Once compartment of this machine holds this incoming blood. A second compartment has a specially treated solution called dialysate. Separating the two compartments is a thin membrane with thousands of tiny holes. This membrane acts like the filters in a healthy kidney. The waste products in the blood pass through the holes into the dialysate. Blood cells, protein, and other vital substances are too large to pass through the holes. They remain in the first compartment and are returned to the body. Blood is removed from an returned to the body at the same time. Only a small amount is absent from the body at once. Dialysate flows constantly during dialysis. After it picks up waste products from the blood, it is discarded down the drain. For home hemodialysis, a partner (such as a relative or technician) must help the person and stay during the procedure. Both the patient and the dialysis partner must take training at a certified facility. This training takes for to six weeks. Hemodialysis is not perfect for everyone. Some people have health complications. These include progressive nerve damage, problems regulating insulin dosages, malnutrition, increased rates of infection, and increased problems accessing the blood vessels. Sometimes, these complications are the result of diabetes, not of hemodialysis. Hemodialysis can cause other problems as well. These include high or low blood pressure, upset stomach or vomiting, anemia, and bone disease. -Peritoneal Dialysis- Many doctors think peritoneal dialysis a better treatment than hemodialysis. There are a variety of methods. The two most common forms are continuous ambulatory peritoneal dialysis (CAPD) and automated peritoneal dialysis (APD). APD is also called continuous cyclic peritoneal dialysis (CCPD). The principles for peritoneal dialysis are similar to those for hemodialysis. But instead of blood being cleaned in an artificial kidney, the body itself is used as a filter. In peritoneal dialysis, wastes are filtered out of the blood through the peritoneum. The peritoneum is a thin membrane that lines the abdominal cavity. A small catheter is placed surgically in the lower abdomen. This catheter remains in the person indefinitely. Usually, the catheter is changed if it doesn't work or if it becomes infected and the infection won't heal. In peritoneal dialysis, a cleansing fluid (dialysate)is poured into the abdominal cavity through the catheter. Waste products pass from the blood vessels through the peritoneal membrane and into the dialysate. After a while the dialysate--with the waste products--is drained from the abdomen. People can perform CAPD themselves by connecting a flexible plastic bag filled with dialysate to a piece of tubing attached to the catheter. Next, the bag is raised to shoulder height. Gravity makes the dialysate flow down into the abdominal cavity. After the bag is empty, it can be disconnected. Some people leave the bag there, but roll it up and place it under their clothing. When the dialysate is in the abdomen, wastes and excess water pass from the tiny blood vessels in the peritoneal membrane into the dialysate. The person can move around freely and perform most daily activities. Afterward, the bag is again connected to the catheter and lowered below the abdomen. Gravity now makes the dialysate containing waste products drain out. Once the bag is full, it is discarded. Then a new container of dialysate is connected, and the process is repeated. An exchange, which includes draining the solution and adding new dialysate, takes about 45 minutes. Usually the dialysate remains in the abdomen 4 to 6 hours before being exchanged. At night, the dialysate is left in for about 8 hours. The exchange of dialysate needs to be done three to five times a day. CAPD has several advantages over hemodialysis. First, it prevents major changes in body chemistry and fluid levels. Preventing large fluid gains may reduce stress on the heart and blood vessels. Second, people using this treatment are not tied to a machine. They can eat a more liberal diet and are better able to hold a job, go to school, or travel. Third, they have better control of blood pressure levels and less anemia. Fourth, they can put insulin in the peritoneal cavity with the dialysate. Insulin taken this way better controls blood glucose. The major problem with CAPD is infection, which can occur in the abdomen or at the catheter. A person using CAPD must keep the catheter area clean and follow all procedures carefully. Some people get lower back problems and weak abdominal wall muscles or a hernia. CAPD is not for everyone. A person must see well and have good motor skills. CCPD is similar to CAPD in that the exchange of dialysate and blood is done in the abdominal cavity. The difference is that in CCPD, the exchange is done automatically by a machine called a cycler. A cycler delivers the dialysate and drains it. It does not need to be done so manually. The exchange of dialysate usually occurs at night during sleep. The cycler does three to five short exchanges during the night. When the person using it wakes up, he or she unhooks the cycler from the catheter. Before disconnecting, new dialysate is pumped into the abdomen. That solution dialyzes during the day and then is drained in the evening. This type of peritoneal dialysis may be ideal for people unable or unwilling to do CAPD. It is also better for people who do not see well, those prone to low blood pressure, and those who have weak abdominal wall muscles. The problems of CCPD are the same as with CAPD. Putting insulin into the peritoneal cavity is harder with CCPD. -The Bottom Line- All treatments for ESRD cost a lot of money. Dialysis, depending on the type, can cost $20,000 to $30,000 a year. Costs of kidney transplants vary more widely, in part because the costs of removing, preparing and transporting the donor's kidney vary a lot. But you can expect to pay tens of thousands of dollars for a transplant. Most insurance plans, including Medicare, will help pay for the costs of dialysis and kidney transplantation. Check with your insurer about its policies. American Diabetes Association Printed with Permission. May 7, 1996. File distributed by the American Diabetes Association. The material in this file is subject to change, for more information on this file, please contact the American Diabetes Association.