If your kidneys are on their way to being damaged by diabetic nephropathy (kidney disease caused by diabetes), doctors can detect microalbuminuria in your urine. A healthy kidney permits only a tiny amount of albumin, a protein in the blood, to enter the urine. However, a kidney being damaged by nephropathy is unable to hold back as much albumin, and the level in the urine increases, causing microalbuminuria.
Recent evidence suggests, however, that an abnormal amount of albumin in the urine is not always present when diabetic neuropathy is developing. A study in Diabetes Care in January 2004 showed that as many as 25 percent of people with diabetes have kidney disease even though there is no increase in the albumin in their urine. Blood tests for kidney function show some loss of function, yet the test for increased albumin is negative. In other words, the absence of microalbuminuria does not always indicate that no kidney damage is taking place. Rather, this finding suggests that treatment with drugs that protect the kidneys should be done for all patients with diabetes, not just those with microalbuminuria.
For three-quarters of the patients in the early stages of kidney disease, however, the amount of albumin in your urine is so small that it won't trigger a positive result when the traditional urine dipstick test is used. Therefore, your doctor should perform a more sophisticated test for microalbuminuria (the presence of tiny but abnormally high amounts of albumin in your urine). This test can be done by collecting a 24-hour urine specimen (meaning you save all the urine you produce in 24 hours and have it tested), by taking a random urine sample, or by collecting a specimen over a certain time period, usually four hours. If the level of albumin is abnormally high, it needs to be checked once again to be certain, because some factors (such as exercise) can trigger a false positive test. A second positive test should lead to action to protect your kidneys.
Because microalbuminuria can be detected about five years before a urine dipstick would test positive for albumin, you have time to treat the onset. Furthermore, treatment during the stage of microalbuminuria can reverse the kidney disease. After macroalbuminuria is found using the dipstick method, the disease can be slowed but not stopped.
If you have had type 1 diabetes for five years or more, or if you've recently been diagnosed with type 2 diabetes, your doctor must check for microalbumin-uria unless you've already tested positive for albumin with a urine dipstick. If your test comes back negative, you should have it rechecked annually.
In June 2003 in the New England Journal of Medicine, researchers showed that microalbuminuria does not always lead to kidney failure. Patients with type 1 diabetes who improved their blood glucose levels, blood pressure, and abnormal blood fats (which I discuss in the next section) experienced a decline in microalbuminuria and, therefore, a decline in kidney damage. The levels of improvement indicated by this study are as follows:
¡^ Lowered blood glucose as indicated by a hemoglobin A1c of less than 8 percent (see Chapter 7)
¡ Lowered blood pressure, with the upper number (the systolic blood pressure) kept under 115 mg mercury
¡^ Cholesterol kept under 198 mg/dl (5.12 mmol/L)
¡^ Triglycerides kept below 145 mg/dl (1.64 mmol/L)
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Diabetes is a disease that affects the way your body uses food. Normally, your body converts sugars, starches and other foods into a form of sugar called glucose. Your body uses glucose for fuel. The cells receive the glucose through the bloodstream. They then use insulin a hormone made by the pancreas to absorb the glucose, convert it into energy, and either use it or store it for later use. Learn more...