Research Activities, January 2014
Some blacks with chronic kidney disease are at particularly high risk for adverse outcomes
Blacks with chronic kidney disease (CKD) have worse outcomes if they have high levels of protein in their urine (proteinuria) and low glomerular filtration rates (GFRs), according to a new study. Previous studies have shown that blacks in the United States have rates of progression from CKD to end-stage renal disease (ESRD) that are 3.5 times higher than the progression rates for whites.
Some of this difference in CKD progression is related to known risk factors that are more prevalent in blacks (proteinuria, hypertension, lower socioeconomic status, coronary disease, and high serum cholesterol). After controlling for other known risk factors, the researchers examined whether a patient's GFR level changed the relationship between proteinuria and CKD progression or death. They looked at 1,094 black patients with high blood pressure and GFR between 20 and 65 mL/minute per 1.73 m2—603 with high baseline GFR (at least 45 mL/min per 1.73 m2) and 491 with low baseline GFR (less than 45 mL/min per 1.73 m2). These individuals were enrolled in the African American Study of Kidney Disease.
A clinical composite outcome (death, GFR decline, progression to ESRD) was more common among patients with low versus high baseline GFR (44.9 vs. 9.9 percent). A renal composite outcome (GFR decline or ESRD) also appeared more often in the patients with lower baseline GFR than those with higher baseline GFR (36 vs. 13.8 percent). The risk of the clinical composite outcome with a doubling of proteinuria was increased by 30 percent with a GFR of 50 mL/min per 1.73 m2 versus 55 percent for a GFR of 25. The study was funded in part by AHRQ (HS19178).
More details are in "Interaction between GFR and risk factors for morbidity and mortality in African Americans with CKD," by Kevin F. Erickson, M.D., Janice Lea, M.D., M.S.C.R., and William M. McClellan, M.D., M.P.H., in the Clinical Journal of the American Society of Nephrology 8(1), pp. 75-81, 2013.