Understanding Diabetic Kidney Disease
Too often, diabetes leads to kidney disease. But it doesn't have to. When kidney problems are caught early, you can take steps to prevent more serious kidney disease. That's why it's 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 seen and treated, the kidneys become more diseased over time. Large amounts of albumin leak into the urine. This is called macroalbuminuria. After several years, 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.
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.
A blood test called glomerular filtration rate (GFR) checks how well your kidneys are working. A GFR can be measured directly, but it's a complicated process. 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 caused by normal wear and tear on muscles. Cystatin C is a waste product that is made constantly in your body. It's found in different fluids, including blood, spinal fluid, and breastmilk. 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.
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. 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 cut your risk for microalbuminuria by a third. Like diabetes, 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.