Protein in the Urine Spells Kidney Failure for African Americans

Newswise — Washington, DC (August 26, 2011) — African Americans are four times more likely to develop kidney failure than whites. A new study has found that a condition that occurs when the kidneys are damaged and spill protein into the urine contributes to this increased risk.

The study, conducted by William McClellan, MD of Emory University and his colleagues, appears in an upcoming issue of the Journal of the American Society Nephrology (JASN), a publication of the American Society of Nephrology.

The investigators analyzed information from 27,911 individuals (40.5% of whom were African Americans). Among the major findings:•After an average follow-up of 3.6 years, 133 individuals developed kidney failure.•There were 96 cases of kidney failure among African Americans and 37 among whites.•Kidney failure was most common in individuals who excreted large amounts of protein in their urine.•African Americans were more likely to excrete large amounts of protein in their urine than whites.

The investigators speculate that several factors may explain why African Americans tend to excrete more protein in their urine. These could include blood pressure and other heart-related factors, obesity, smoking, vitamin D levels, genetic differences, income, and birth weight. These factors may act at different times during an individual’s life to affect kidney health.

“Our large nationwide study brings attention to higher levels of urinary protein excretion as important contributors to the increased incidence of kidney failure experienced by blacks,” said Dr. McClellan. Treating urinary protein excretion may help reduce racial disparities related to kidney failure as well as reduce the rate of progression to kidney failure for all individuals.

Study co-authors include David Warnock, MD, Suzanne Judd, PhD, Paul Muntner, PhD, Leslie McClure, PhD, George Howard, DrPh (University of Alabama at Birmingham); Reshma Kewalramani, MD (Amgen Corporation); Mary Cushman, MD (University of Vermont); and Britt Newsome, MD (Denver Nephrologists, PC).

Disclosures: This research project is supported by a cooperative agreement U01 NS041588 from the National Institute of Neurological Disorders and Stroke, National Institutes of Health, Department of Health and Human Services. Additional funding was provided by an investigator-initiated grant-in-aid from Amgen Corporation. Amgen did not have any role in the design and conduct of the study, the collection, management, analysis, and interpretation of the data, or the preparation or approval of the manuscript. The manuscript was sent to Amgen for review prior to submission for publication.

The article, entitled “Albuminuria and Racial Disparities in the Incidence of End-Stage Renal Disease,” will appear online at http://jasn.asnjournals.org/ doi 10.1681/ASN.2010101085

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