Common Tests of Kidney Function May Not Help Type 2 Diabetics

New York, NY
November 10, 2003

Recent research suggest that common test used to identify whether people have the early stages of kidney disease may fail to find the disease in hundreds of thousands of type 2 diabetics.

“In many people with diabetes, the first signs of kidney disease can be deceptive, and traditional testing could miss many people when they would benefit most from treatment -- in the early stages of their condition,” according to Brian Pereira, MD, president of the National Kidney Foundation.

In the recent study, approximately 30 percent of people with type 2 diabetes and early kidney disease did not exhibit trace amounts of protein in their urine or characteristic changes in the retina of their eyes—two common signs of early kidney disease in these individuals. These results suggest that, among the 1 million adults 40 and up in the U.S. who have type 2 diabetes and an advanced form of kidney disease, simple eye and urine tests would miss the condition in roughly 300,000 people.

“The results suggest that type 2 diabetics should, on a regular basis, undergo additional tests of kidney function – such as the glomerular filtration rate, or GFR, which measures how well the kidneys are filtering the blood,” adds Pereira. “The NKF’s Chronic Kidney Disease guidelines recommend checking people at increased risk for chronic kidney disease for GFR as well as urine albumin.”

Diabetes is the leading cause of kidney failure in the United States. Because a cure for diabetic kidney disease has not yet been found, treatment to prevent diabetic kidney disease should begin early, before kidney damage develops.

According to the National Kidney Foundation, 17 million Americans, or about 6.2 percent of the population, have diabetes, a condition characterized by high levels of blood sugar, resulting from insufficient production of insulin or defects in insulin action in the body. The vast majority has type 2 diabetes, also called noninsulin-dependent diabetes, which is associated with obesity and often diagnosed in adulthood.

Given their risks, diabetics are frequently tested to determine how well their kidneys are functioning. In one such test, doctors examine their eyes to look for characteristic changes in the blood vessels of the retina. In another, urine samples are screened for the presence of protein, an indication the kidneys are leaking some of the substances the body needs to survive.

While most people with kidney disease and type 1 diabetes—or insulin-dependent diabetes–develop changes in the eye, urine, or both, the recent report showed that is often not the case for the majority of people with diabetes.

Obesity and its associated diseases are on the rise, and type 2 diabetes is no exception. Given this trend and improvements in how the condition is treated, researchers predict that the number of people with end-stage kidney failure—who must often go on dialysis or receive a transplant to survive—may double in the next 10 years, at a cost to taxpayers of $28 billion each year.

For more information about diabetes and kidney disease, contact the National Kidney Foundation at (800) 622-9010.