US Kidney Failure Rates Stabilize, Ending A 20-year Climb; But Troubling Racial Disparities Persist

In 2003, the rate for new cases of kidney failure was 338 permillion population, down slightly from 2002 and continuing a four-yeartrend, finally allowing researchers to be cautiously optimistic thatrate decreases have not happened by chance. The average annual increasehas been less than 1 percent since 1999, compared to an average 5percent in the previous decade, according to research publishedrecently by NIDDK's U.S. Renal Data System (USRDS) at www.usrds.org andbeing presented next month at the annual scientific meeting of theAmerican Society of Nephrology.

Diabetes and high blood pressure remain the leading causes of kidneyfailure, accounting for 44 percent and 28 percent of all new cases,respectively. The most striking trends were found in diabetes, whererates for new cases in whites under age 40 were the lowest since thelate 1980's, in stark contrast to rates for their African Americancounterparts, which have not budged.

"It's gratifying to see progress, however small, and to know that NIDDKactivities undoubtedly have had a hand in that success," said Paul W.Eggers Ph.D., NIDDK's co-director for the USRDS. "But persistentdisparities are sobering."

Credit for recent gains likely goes to clinical strategies proven inthe 1990s to significantly delay or prevent kidney failure:angiotensin-converting enzyme inhibitors (ACE-inhibitors) andangiotensin receptor blockers (ARBs), which lower protein in the urineand are thought to directly prevent injury to the kidneys' bloodvessels; and careful control of diabetes and blood pressure. The launchof private and government programs to improve care and increaseawareness coincided with these developments, including NIDDK's NationalKidney Disease Education Program (NKDEP).

NKDEP encourages early diagnosis and management by increasing awareness about:

• the connection between diabetes, high blood pressure and kidney disease
• strategies proven to prevent or delay kidney failure
• estimating kidney function (eGFR) to find kidney disease earlier
• efforts to standardize testing for kidney disease and encourage more labs to automatically report eGFR, and
• time-saving tools for health professionals at www.nkdep.nih.gov, including eGFR calculators that eliminate most of the work to estimate kidney function; and a letter template, which automatically calculates patient-specific eGFR, generates a list of next steps based on kidney disease stage and is designed to improve communication between kidney specialists and primary care physicians.

Despite incremental successes in preventing kidney failure and inimproving health and survival of people who have it already, theincreasing and aging U.S. population means that more people than everbefore are getting and living with the disease. In 2003, nearly 537,000people received dialysis or a kidney transplant. The cost to Medicarewas $18.1 billion, with another $9.2 billion borne by private insurersand patients. Another 10 million people in the United States haveearlier kidney disease; most don't know they have it, let alone thatthe disease increases the risk for premature death, heart attacks,strokes, and other problems.

The research also found both encouraging and discouraging news aboutthe quality of care for people with chronic kidney disease (CKD), anearlier stage that precedes kidney failure. Tests to find kidneydisease at the earliest, most-treatable stages are not widely used.Only 10 percent of the general Medicare population had a blood test andonly 5 percent had urine tested for kidney disease. But, whileACE-inhibitors and ARBs are still underutilized, there has been adramatic increase in their use. In the past decade, the use of thesedrugs doubled among people over age 60 with CKD, from 16 percent to 32percent of patients, and nearly half of those who also had diabetes orhypertension or congestive heart failure used them.

"We could prevent or delay a lot more kidney failure, simply by usingthe box of tools that are already in the trunk," said Josephine P.Briggs, M.D., a kidney specialist and director of NIDDK's Division ofKidney, Urologic, and Hematologic Diseases.

USRDS research depends oncollaborations with other agencies of the U.S. Department of Health andHuman Services (HHS), especially the Centers for Medicare and MedicaidServices, but also the United Network for Organ Sharing and the Centersfor Disease Control and Prevention. Patient registries for othercountries also contribute data for analyses.

NIDDK, part of the National Institutes of Health (NIH), conducts andsupports research and education programs on kidney disease anddiabetes, among others. Learn more about NIDDK programs and diseases atwww.niddk.nih.gov.