Predicting the risk for end-stage kidney disease (ESKD) using only estimated glomerular filtration rate (eGFR) is inferior to using the 4-variable kidney failure risk equation (KFRE), which factors in age, sex, and urinary albumin to creatinine ratio in addition to eGFR, according to investigators.
A team from the Chronic Renal Insufficiency Cohort (CRIC) study compared the performance of all 5 equations from the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) against the 4-variable KFRE score in 3767 patients (aged 21-74 years) from the 2003-2008 CRIC study, of whom 856 progressed to ESKD. Of the full cohort, 1581 self-reported Black race.
In both Black and non-Black patients, a 4-variable KFRE score higher than 20% had greater sensitivity (68-78% vs 42-66%) but similar specificity (94-97% vs 95-98%) compared with an eGFR threshold of less than 20 mL/min/1.73 m2 for predicting a 2-year risk of ESKD. At any given level of specificity, the sensitivity of the 4-variable KFRE score vs eGFR alone was more than 10% higher among both Black and non-Black participants, the investigators reported.
“Our results show that eGFR alone is an excellent predictor of ESKD, but the KFRE score had substantially better discrimination than eGFR alone in our study, regardless of which eGFR equation was used.” Jiang He, MD, PhD, of Tulane University in New Orleans, Louisiana, and colleagues wrote in the Annals of Internal Medicine. “Therefore, the value of the KFRE score may be an important additional consideration in addressing the current controversy surrounding eGFR race adjustment.”
A joint task force of the National Kidney Foundation and American Society of Nephrology recently recommended the 2021 CKD-EPI creatinine equation refit without race and increased measurement of cystatin C. The current study examined the latest equations as well as the 2009 and 2012 CKD-EPI equations based on creatinine and/or cystatin C, with and without a race consideration. The 2021 creatinine equation without race adjustment improved calibration among Black participants. The 6- and 8-variable KFRE were less prognostic compared with the 4-variable KFRE. The 4-variable KFRE score still underestimated ESKD risk, especially for Black patients. Findings from this US cohort may not be generalizable to global populations.
In an accompanying editorial, Akinlolu Ojo, MD, PhD, MBA, of the University of Kansas Medical Center in Kansas City, emphasized that even greater efforts — beyond revising eGFR equations — are needed to address enduring kidney health inequities between Black and Non-Black patients.
Bundy JD, Mills KT, Anderson AH, Yang W, Chen J, He J; for the CRIC study investigators. Prediction of end-stage kidney disease using estimated glomerular filtration rate with and without race: a prospective cohort study. Ann Intern Med. Published online January 10, 2022.doi:10.7326/M21-2928
Ojo A. Eliminating racial inequities in kidney health: much more than revised estimating equations. Ann Intern Med. Published online January 10, 2022.