Acute Kidney Failure Is More Prevalent Among African-Americans

Results of a recent community-based study suggest that African-American patients are at higher risk for acute kidney injury (AKI) than Caucasians — a difference that appears to be related to disparities in income and socioeconomic status.

At Kidney Week 2013, the American Society of Nephrology's annual meeting held November 5-10, 2013, in Atlanta, GA, Morgan Grams, MD, MHS, a nephrologist at The Johns Hopkins University in Baltimore, MD, said socioeconomic, genetic, and clinical risk factors have been proposed as possible causes of the disparity in AKI risk, but the extent to which those factors affect risk had remained unknown. That’s why Grams and her colleagues evaluated the impact of those factors on acute kidney injury for their study.

Their community-based prospective Atherosclerosis Risk in Community (ARIC) cohort study included 2,244 middle-aged African-American patients and 8,350 middle-aged Caucasian patients. All study participants were followed from their baseline study visit between 1996 and 1999 until their first acute kidney injury with hospitalization, their development of end-stage renal disease, their death, or December 31, 2010, whichever came first.

The group of African-American study participants was younger, more female, and had higher baseline estimated glomerular filtration rate (eGFR) and prevalence of microalbuminuria than the Caucasian group. The African-American patients also had lower annual family incomes, lower education levels, and less likelihood of having health insurance.

According to the researchers, 31.8% of the African-American group had incomes less than $12,000 per year, compared to 5% of the Caucasian group; 61.5% of the African-Americans had health insurance, compared to 92.7% of the Caucasians; 11.9% of the African-Americans had Medicaid insurance, compared to 5.3% of the Caucasians; and 34.0% received medical care in the emergency department, compared to 14.1% of the Caucasians.

There were 207 acute kidney events among the African-American group, in contrast to 608 among the Caucasians. In addition, the unadjusted incidence of AKI with hospitalization was 8.1 cases per 1,000 person-years among the African-American group, compared to 6.2 cases per 1,000 person-years among the Caucasian group.

The increased risk of AKI remained after the researchers adjusted for demographics, cardiovascular risk factors, kidney markers, and time-varying number of hospitalizations. High-risk variants of the Apolipoprotein L1 (APOL1) gene were not significantly associated with AKI among African-American patients, even after considering the competing risk of end-stage renal disease. When the authors accounted for the differences in income and insurance by race, the association was no longer significant.

The researchers hypothesized that the higher risk of AKI among African-American patients may largely be caused by differences in socioeconomic status, especially family income and the lower probability of having health insurance. Although the authors found no statistically significant association with APOL1, they explained that their study may have been underpowered to detect the difference. The investigators suggested that increased access to quality health care would lower AKI rates and reduce racial disparities.