Many Diabetics May Not Know They Have Kidney Disease

New York, NY
June 27, 2003

The current screening strategy for kidney disease among people with type 2 diabetes mellitus is missing an estimated 300,000 people in the U.S., according to a study in the June 25 issue of the Journal of the American Medical Association (JAMA).

Researchers at Loyola University Health System, Maywood Ill., found 30 percent of adult diabetic patients with kidney disease do not have retinopathy (eye disease) or albuminuria (protein in urine), factors physicians screen for and associate with chronic kidney disease due to type 2 diabetes mellitus.

"Delays in diagnosis and treatment as a result speeds progression to kidney failure," said lead author Holly J. Kramer, M.D., MPH, assistant professor, department of epidemiology and preventive medicine, Loyola University Chicago Stritch School of Medicine.

Over the next 10 years, the number of patients in the U.S. with kidney failure (end stage renal disease┬żESRD) is expected to double. By 2010, the cost of ESRD may exceed $28 billion annually, an amount billed directly to the Medicare program and the U.S. taxpayer, according to the United States Renal Data System, Bethesda, Md., of the National Institute of Diabetes and Digestive and Kidney Diseases. Nearly half of all new cases of ESRD are attributed to type 2 diabetes.

Type 2 Diabetes

"To screen for kidney disease, physicians should estimate the glomerular filtration rate (GFR) using serum creatinine (a measurement of kidney function) in patients with type 2 diabetes, in addition to screening for presence of albuminuria and diabetic retinopathy," said Kramer. "The GFR is a measure of kidney filtering capacity. A decrease in GFR always occurs before kidney failure.

"Patients with type 2 diabetes should ask their doctor for their GFR on an annual basis," said Kramer.

For the study, Dr. Kramer and colleagues examined data from 1,197 people age 40 or older who have type 2 diabetes mellitus.

"We found a substantial number of these patients had reduced GFR without retinopathy or albuminuria," said Kramer. "Chronic kidney disease is defined as a low GFR.

"Therefore, the current strategy of screening for albuminuria and retinopathy alone among type 2 diabetic adults may not be sufficient for the early detection of kidney disease," said Kramer.

Co-authors of the study with Dr. Kramer are Quan Dong Nguyen, M.D., Johns Hopkins Medical Institutions, Baltimore, Md.; Gary Curhan, M.D., Massachusetts General Hospital and Brigham and Women's Hospital, Boston; and Chi-yuan Hsu, M.D., University of California at San Francisco.

Visit the Loyola University Health System Web site www.luhs.org for more information.