Serum Creatinine Concentrations and Race/Ethnicity in Patients Receiving Hemodialysis

According to Cynthia Delgado, MD, and colleagues, there are few data available on differences in serum creatinine concentration between Black and non-Black individuals. To date, those differences among groups defined by race and ethnicity have been attributed to differences in muscle mass. 

The researchers conducted a data analysis to examine differences in serum creatinine by race and ethnicity in a cohort of patients receiving hemodialysis, and to determine whether the differences persisted following adjustment for proxies of muscle mass. The analysis included data on 501 participants in the ACTIVE/ADIPOSE (A Study to Investigate the Value of Exercise in ESKD/Analyses Designed to Investigate the Paradox of Obesity and Survival in ESKD) study. Eligible participants had been receiving hemodialysis for more than 1 year. 

The researchers sought to examine the independent associations among race/ethnicity (Black, Asian, non-Hispanic White, and Hispanic), serum creatinine, and intracellular water (ICW; L/m²; a proxy for muscle mass). The associations were identified using multivariable linear regression with adjustment for several demographic, clinical, and laboratory characteristics. ICW was derived by whole-body multifrequency bioimpedance spectroscopy. The association of race and ethnicity with serum creatinine concentration was examined with and without adjustment for ICW. 

Serum creatinine concentrations were higher among Black, Asian, and Hispanic patients compared with non-Hispanic White patients (+1.68 mg/d; +1.61 mg/dL; +0.83 mg/dL, respectively). Overall, there was an association between ICW and serum concentration (0.26 ng/dL per L/m² ICW). The association was not statistically significantly different by race and ethnicity. After adjustment for ICW, the association between Black, Asian, and Hispanic race/ethnicity and serum creatinine concentration remained significant. 

“Among patients receiving dialysis, serum creatinine was higher in Black, Asian, and Hispanic patients than in non-Hispanic White patients,” the researchers said. “Differences in ICW did not explain the differences in serum creatinine concentration across race groups.” 

Source: Journal of the American Society of Nephrology