November 23, 2010

Race Associated with Declining Kidney Function

(Ivanhoe Newswire) -- Kidney function declines faster in African Americans and some Hispanic groups compared to white Americans, according to this study. "Racial/ethnic differences are present early, before chronic kidney disease (CKD) has been established," Carmen A. Peralta, MD (University of California, San Francisco) was quoted as saying.

The researchers analyzed data on nearly 5,200 U.S. adults, all entering the study with normal kidney function based on a large study of heart disease risk factors (the Multi-Ethnic Study of Atherosclerosis). Two different "generalized estimating equations" were used to assess changed in kidney function, based on five-year follow-up data. The study compared white, black, Hispanic, and Chinese Americans to look for racial/ethnic differences in the age-related rate of kidney function.

In African Americans a faster annual rate of decline was shown. By one equation, decline was about 60 percent faster for African Americans versus white participants. "The observed differences were not fully explained by traditional risk factors," such as cholesterol levels, body weight, smoking, diabetes, or high blood pressure Peralta added. Faster kidney decline was also seen in Hispanic participants, but the effect varied based on country of origin. Dominicans had the fastest rate of decline, followed by Puerto Ricans. All other Hispanic subgroups, as well as Chinese Americans, demonstrated a rate of decline in kidney function similar to that of whites.

End-stage renal disease (ESRD) disproportionately affects African-Americans and Hispanics. "Studies have suggested that this is more likely due to faster rates of progression from established CKD," Peralta explains. "Whether or not these differences in kidney function decline are present at earlier stages of kidney dysfunction is not well known."

The results suggest that people of certain racial and ethnic groups may be at risk for faster declines in kidney function, even if they are free from CKD. "This reflects a new opportunity to study how to best identify persons at high risk and to investigate prevention strategies for CKD," Peralta concludes.

The study had some limitations, especially that kidney function was assessed using estimating equations, rather than measured directly.

SOURCE: American Society of Nephrology's 43rd Annual Meeting and Scientific Exposition held in Denver, CO from November 16-21, 2010