Researchers who analyzed 20-year follow-up data from a prospective study found that African Americans have a higher incidence of chronic kidney disease (CKD) than whites in part because of albuminuria.

“This finding provides an important contrast to cross-sectional studies reporting a higher CKD prevalence among whites compared with African Americans,” the authors concluded in a paper published in the Clinical Journal of the American Society of Nephrology (2012;7:101-107).

The study compared the incidence of CKD among young African-American and white adults who participated in the community-based Coronary Artery Risk Development in Young Adults (CARDIA) study.

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The study population included 4,119 subjects aged 18-30 years with an estimated glomerular filtration rate (eGFR) of 60 mL/min/1.73 m2 or higher. The researchers, led by Paul Munter, PhD, of the University of Alabama in Birmingham, defined development of CKD as a decrease in eGFR to below 60 and a 25% or greater decline in eGFR at study visits conducted 10, 15, and 20 years after baseline.

Forty-three CKD cases developed during follow-up: 29 (1.4%) among African Americans and 14 (0.7%) among whites, a significant difference between the races. After adjusting for age, gender, body mass index, systolic blood pressure, fasting plasma glucose, and high-density lipoprotein cholesterol, researchers found that CKD was 2.5 times more likely to develop in African Americans than in whites, Dr. Munter’s group reported. In a multivariable analysis that accounted for albuminuria at year 10, however, CKD was only 12% more likely to develop in African Americans than in whites at year 15 or 20.

At the year 10 visit, the geometric mean albuminuria level was 8.2 mg/g among African Americans compared with 6.6 mg/g among whites.

It is well established that African Americans have a higher incidence of end-stage renal disease than whites, the researchers noted. Recent data from the U.S. Renal Data System shows that ESRD is four times more likely to develop in African Americans than in whites, they pointed out. “Our study findings suggest that [the] incidence of earlier stages of kidney disease also occurs more frequently among African Americans,” the authors observed.

Dr. Munter and his colleagues said it is possible that African Americans have more severe kidney disease that progresses more rapidly to ESRD. It is noteworthy that six of the seven participants with ESRD in their study were African American, they stated.