Early diagnosis

New practice guidelines take aim at chronic kidney disease

More than 20 million AmericansÑone in nine adultsÑhave chronic kidney disease. Most don't even know it. Another 20 million are at increased risk for developing the disease.

This surprising surge in prevalence is among several major findings included in the National Kidney Foundation's new clinical practice guidelines, aimed at helping physicians diagnose this under-treated medical condition earlier and more easily than before.

Dr. Andrew S. Levey chaired the work group that developed the new practice guidelines. © Mark Morelli

"Americans who have diabetes, high blood pressure or a family history of kidney disease should ask their physicians for routine blood and urine tests to diagnose chronic kidney disease," said Dr. William F. Keane, president of the National Kidney Foundation (NKF). The new guidelines were announced February 5 at a news conference in Washington, D.C., and also were published in the February issue of the American Journal of Kidney Diseases.

Early detection is key
"These tests can detect chronic kidney disease in its early stages, when lifestyle changes and medication can be prescribed to delay or prevent the progression of kidney disease and its complications, including the development of heart disease," Keane said.

Left untreated, chronic kidney disease can lead to kidney failure, requiring transplant or dialysis for a patient to survive. With the number of kidney failure patients expected to more than double to 650,000 by 2010Ñat a projected cost of $28 billion to taxpayersÑthe guidelines could not come at a better time.

The NKF recommends that all individuals who are at increased risk for chronic kidney disease have their blood pressure measured and their blood and urine tested for signs of impaired kidney function. In addition to people with diabetes, high blood pressure or a family history of kidney disease, the guidelines identify older Americans, African Americans, Hispanics, Asians and Pacific Islanders as being at increased risk.

"Recent research indicates that kidney failure can be prevented or delayed if chronic kidney disease is diagnosed early enough and treated properly," said Dr. Andrew S. Levey, the Gerald J. and Dorothy R. Friedman Professor of Medicine at Tufts and chairman of the work group that developed the evidence-based guidelines.

A powerful tool
"Three routine testsÑblood for creatinine, urine for protein and measurement of blood pressureÑenable providers to detect kidney disease in its early stages," Levey said. "The guidelines also include a five-stage clinical action plan based on the severity of kidney disease, which offers all physiciansÑnot just kidney specialistsÑa powerful tool similar to those used for managing other chronic conditions.

"Our new definition also provided us with criteria for analyzing data from the third National Health and Nutrition Examination Survey and calculating the first-ever prevalence figures for each stage of the disease," said Levey, also chief of nephrology at Tufts-New England Medical Center. In April, Levey will receive the NKF's first Garabed Eknoyen Award for his work in chronic kidney disease.

The guidelines recommend estimating glomerular filtration rate, or GFR, from the level of creatinine in the blood and checking for persistent protein in a patient's urineÑknown as proteinuriaÑas the best methods for diagnosing early kidney damage.

The widespread belief that measurement of GFR and the detection of proteinuria require a 24-hour urine collection has discouraged health care providers from doing these tests routinely. However, the new guidelines say that the GFR level and persistent proteinuria can be estimated just as accurately from blood and urine tests collected during a routine office visit.

The clinical practice guidelines for chronic kidney disease, which are available on NKF's web site at www.kidney.org and in book and CD-ROM formats, are the newest set of guidelines to be developed by the National Kidney Foundation through its Kidney Disease Outcomes Quality Initiative or K/DOQI. Building on the continuing success of its guidelines to improve outcomes for dialysis patients, NKF broadened the scope of the project in 2000 to include chronic kidney disease.

"With the release of these new guidelines, the potential benefit of K/DOQI will expand from 300,000 dialysis patients to more than 40 million Americans who have chronic kidney disease or who are at increased risk for developing it," said Dr. Garabed Eknoyan, K/DOQI co-chair and professor of medicine at Baylor College of Medicine in Houston.

The guidelines are the result of two years of work by volunteer experts in nephrology, pediatric nephrology, epidemiology, laboratory medicine, nutrition, gerontology and social work who conducted a systematic review of evidence published in peer-reviewed medical journals.