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Proteinuria - Kidney Damage and Diabetes

Early Signs of Kidney Disease

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Updated June 25, 2014

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Proteinuria - Kidney Damage and Diabetes

You kidneys perform many important functions, such as filtering the waste products from your body and keeping protein in the body.

National Kidney Foundation

Proteinuria is a condition that is often associated with diabetes, especially those who have been living with diabetes for several years. It is one of the complications that can result from diabetes and is an indicator that your kidneys are not properly filtering your blood.

Protein is necessary for your body to function properly: It is used to help protect you from infection, help blood to clot, build muscle and bones, and keep the appropriate amounts of fluid circulating in the body, among other functions. One of your kidney’s main tasks is to filter out waste products while at the same time leaving the proteins in the blood so they can be used for all of the above functions. When the kidney’s filtering system (called glomeruli) begins to break down, small (micro) amounts of protein (also called albumin) get passed into the urine. This is sign of chronic kidney disease (CKD).

What causes the kidney’s filtering system to break down with diabetes?

High blood glucose over a prolonged period of time and/or high blood pressure are the main reasons the filtering system in the kidneys begins to fail. High blood glucose, combined with high blood pressure, puts enormous stress on the kidney’s ability to function properly. As kidney function declines, the amount of protein or albumin that ends up passing through the kidneys increases. If blood glucose and blood pressure are not brought under control, the kidneys will continue to deteriorate to the point where full kidney failure could eventually occur, resulting in a need for kidney dialysis.

What are the symptoms of proteinuria?

Unfortunately, there are no noticeable signs or symptoms in the early stages of proteinuria. The only way to know if protein is leaking into the urine in the early stages is to have a urine test evaluated by a lab. In later stages of proteinuria, when larger amounts of protein have regularly begun passing into the urine, you may notice a foamy texture in the toilet following urination. The protein that is lost in the body through the urine could also cause swelling (edema) in the hands, feet, abdomen and face.

What does the lab test for the urine sample measure?

There are two types of urine tests used to measure the amount of protein in the urine.

  • A collection of urine over a 24-hour period that is submitted to the lab
  • A one-time collection that can be collected at home or on the spot at your doctor’s office.

In recent years, the single urine sample is the most common and convenient. It measures the amount of albumin in the sample and compares it to the amount of waste product from normal muscle breakdown. This waste product is referred to as creatinine. The measurement is called a urine albumin-to-creatinine ratio (UACR).

If your urine contains more than 30 milligrams of albumin for each gram of creatinine, a second test is required to confirm the results and should be performed within one or two weeks after the first. If the second test exceeds 30 mg/g, it indicates that your kidneys are not filtering properly and is a sign of declining kidney function.

Though a urine test is the only reliable way to measure albumin in the urine, a blood test can be performed to measure the amount of creatinine. This test is useful to determine how efficiently your kidneys are filtering the wastes from your blood. The calculation used is called the estimated glomerular filtration rate, or simply eGFR. A test result of less than 60 milliliters per minute (mL/min) indicates the presence of chronic kidney disease.

Can proteinuria be treated?

The primary goals in treating proteinuria is to get both your blood sugar and blood pressure under control. Effective diabetes management means testing your blood glucose often, following a healthy and portion-conscious meal plan, taking insulin as prescribed by your doctor, and exercising regularly. Together, these are your “tools” for managing your blood glucose.

If you also have high blood pressure, you might benefit from some medications that have been found to protect kidney function while helping to control blood pressure. Talk with your doctor about whether those medicines are appropriate for you. The American Diabetes Association recommends that people with diabetes maintain a blood pressure below 130/80.

Once protein has been detected in your urine, you should have a creatinine blood test at least once a year to monitor how well your kidneys are filtering out waste products.

Sources:

Johns Hopkins Alerts. "Microalbuminuria: The Early Sign of Kidney Disease."

National Kidney & Urologic Diseases Information Clearinghouse. "Proteinuria."

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