Error in GFR calculation with exclusion of patient race

1. The exclusion of patient race from glomerular filtration rate (GFR) estimation resulted in systematic error that significantly underestimated GFR in African American individuals more so than non-African Americans.

Evidence Rating Level: 2 (Good)

Glomerular filtration rate (GFR), an integral component of establishing drug dosing, prognosis, and treatment of patients with kidney disease, is often measure indirectly through serum creatinine levels to develop an estimate (eGFR). This estimation is adjusted by height, weight, age, sex, and race due to the susceptibility of serum creatinine to muscle mass, diet, and GFR. This investigation of a pooled data set from 10 studies of individuals with and without chronic kidney disease sought to determine whether or not removal of the race variable from the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation would impact accurate outcomes. The major concern and impetus for this research question was that race is a social construct that is often more complicated than one single category. In these cases, eGFR could potentially be inaccurate. A total of 8,254 individuals were included in the development data set (mean [SD] age = 47 [15] years, mean [SD] GFR = 68 [40] mL/min/1.73 m2). Of this group, 31.5% were African American and 43.6% were women. When the race coefficient was removed from the CKD-EPI equation, significant systematic error resulted in the evaluation of African American GFR, such that values were underestimated. Non-African Americans were less impacted by this alteration. The inclusion of variables such as height and weight did not adequately decrease the association of eGFRcr and race (coefficient 1.16 vs 1.15). This study highlights not only the importance of race in these estimates but also suggests that a construct deemed socially-derived rather than biological is still necessary in estimating GFR in those with chronic kidney disease.

Click to read the study in JAMA Internal Medicine

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