Understanding Diabetic Kidney Disease
Too often, diabetes may lead to kidney disease. For that reason it is important that
kidney problems are caught early so you can take steps to prevent more serious kidney
disease from developing. That's why it's also important to check the health of your
kidneys with a microalbuminuria test.
The kidneys filter and clean about 50 gallons of blood every day. This removes waste
products that your body doesn’t need. Diabetes can be hard on the kidneys. When blood
sugar is high, the kidneys filter more blood than normal. Over time, their tiny filters
start to leak. When this happens, substances that normally stay in the blood pass
into the urine. The protein albumin is one of those substances. When small amounts
of albumin appear in the urine (microalbuminuria), this is an early sign of kidney
damage.
If early damage isn't found and treated, the kidneys become more diseased over time.
Large amounts of albumin leak into the urine. This is called macroalbuminuria. Over
a period of time, the kidneys may shut down entirely. The only treatments at that
point are dialysis or a kidney transplant. Dialysis is the cleansing of the blood
by a machine.
Microalbuminuria test
Early kidney disease has no symptoms, so you need a microalbuminuria test to check
to see how well your kidneys are working. The test measures the amount of albumin
in your urine. You may be asked to provide a fresh sample of urine while you're at
your healthcare provider's office. This is called a random (spot) sample. Or you may
be asked to collect your urine for a certain period of time. This might be over 4
hours, 24 hours, or overnight. This is called a timed sample. You'll be given a container
and instructions for collecting your urine. Little or no albumin in the urine means
your kidneys are normal. A moderate amount means early kidney damage. A large amount
means more severe kidney disease.
How often to test
The American Diabetes Association recommends that people who have type 2 diabetes
have a microalbuminuria test every year. People with type 1 diabetes should be tested
once a year if they're older than age 10 or have had diabetes for 5 years or longer.
If you take certain medicines, have high blood pressure, or have more albumin in your
urine than is normal, you may need to be tested more often.
Blood tests
A blood test called glomerular filtration rate (GFR) is often used to find early signs
of kidney disease. A GFR can be measured directly, but there are several steps involved.
Your provider will use a different test known as an estimated GFR or eGFR. This test
is based on the results of other blood tests that measure serum creatinine and serum
cystatin C, along with other information about you. Creatinine is a waste product
that comes from the digestion of protein in your food and the normal breakdown of
muscle tissue. Cystatin C is a small protein made by the cells in your body. When
your kidneys are healthy, they filter creatinine and cystatin C out of the blood so
it can be excreted in your urine. The eGFR level will fall if you have kidney disease.
Treating microalbuminuria
If your test shows that you have microalbuminuria, it's very important that you get
treatment to slow the progression of kidney disease. You'll need to keep your glucose
controlled as much as possible. Staying in your target range can greatly cut the risk
of developing more serious kidney disease. To reduce stress on your kidneys, you'll
also need to control your blood pressure. Your healthcare provider may recommend that
you eat only moderate amounts of protein. Maintaining good heart health by lowering
cholesterol and managing high blood pressure is also important for controlling microalbuminuria.
And if you smoke, talk with your provider about ways to quit. Quitting smoking will
help prevent more kidney damage, as well as many other health problems.
Other changes that may help prevent more kidney disease include losing weight if you're
overweight, eating a low-salt diet, cutting back on the amount of alcohol you drink,
getting more exercise, and not taking NSAIDS, such as ibuprofen.
Two types of medicines are commonly used to slow the progression of kidney disease
by lowering blood pressure. One type is an angiotensin-converting enzyme (ACE) inhibitor,
such as lisinopril, captopril, and enalapril. The other is angiotensin receptor blockers
(ARB), such as losartan. Other medicines may be used to control blood pressure. These
include calcium channel blockers, beta-blockers, and diuretics,
Keep your kidneys healthy
If you have healthy kidneys now, keeping your glucose in your target range can lower
your risk for microalbuminuria by a third. Diabetes along with high blood pressure
is a major cause of kidney disease. Take blood pressure medicine as directed, get
regular exercise, and follow a heart-healthy eating plan. You can do a lot right now
to prevent or delay kidney disease.