Author: John McIntosh
Source: Diabetes Focus, January-March 2006
For people with diabetes, kidney disease is often a silent complication that develops over many years, to devasting effect. The good news? You can prevent it or slow its progress.
Diabetes Focus: How does diabetes affect the kidneys?
Dr. Hostetter: The kidneys are a filter. They adjust the salt balance in the body and remove many toxins that are a result of the metabolism of proteins. High glucose levels damage the small capillaries that run throughout the kidney. The filtering capacity of the kidney drops; toxins, salt and water accumulate; and eventually the person feels sick.
DF: What are the symptoms?
DR.H: There are no symptoms early on. Young, healthy people with type 1 can lose up to 90 percent of their kidney function before they begin to show severe symptoms. That’s why testing is needed to detect the disease early. Everyone with type 2 should have their kidney health checked at diagnosis, because the time between development of diabetes and diagnosis is often enough for the beginnings of microvascular damage to occur. High blood pressure within the small vessels in the kidneys also may happen early on in diabetes. It can be very damaging to kidney function. Toward the end stage of kidney disease, when someone is headed for dialysis or transplant, the patient may have these symptoms: the need to urinate more or less often; a feeling of fatigue or itchiness; loss of appetite; nausea and vomiting; swelling or numbness in the hands or feet; drowsiness; trouble councentrating; muscle cramps.
DF: What kind of test should a person with diabetes have done?
DR.H: You should ask your doctor for a urine test to check something called your albumin levels. Don’t assume he or she will do it; be adamant. Albumin is a protein that begins to be secreted out of the kidneys in greater and greater amounts when there are microvascular complications. There’s also a blood test, called the glomerular filtration rate (GFR) , that checks the filtering function of the kidney. If the filtration rate decreases, that tells us the kidney function is not up to par. You need to ask the doctor to have the lab convert the reading into an estimation of kidney function. After their first tests, everyone with diabetes should be tested at least once a year to keep tabs on how their kidneys are doing.
DF: What can someone do to help prevent or arrest kidney disease?
DR.H: The first step is to prevent type 2 diabetes, even if you are diagnosed with pre-diabetes. Many studies have shown weight control and exercise are effective. Second, if you have diabetes, strict control of glucose levels can slash the risk of developing kidney problems. Third, keeping high blood pressure under control may be just as, or even more, important than glucose control. Taking ACE inhibitors and ARBs along with other blood pressure medications may be essential to controlling blood pressure.