ASN's Mission

To create a world without kidney diseases, the ASN Alliance for Kidney Health elevates care by educating and informing, driving breakthroughs and innovation, and advocating for policies that create transformative changes in kidney medicine throughout the world.

learn more

Contact ASN

1401 H St, NW, Ste 900, Washington, DC 20005

email@asn-online.org

202-640-4660

The Latest on Twitter

Kidney Week

Abstract: TH-PO878

Association of Race-Based vs. Race-Free eGFR With Nutritional Status, Mortality, and ESKD in African Americans With CKD

Session Information

Category: CKD (Non-Dialysis)

  • 2201 CKD (Non-Dialysis): Epidemiology‚ Risk Factors‚ and Prevention

Authors

  • Amin, Sahar, The University of Tennessee Health Science Center College of Medicine, Memphis, Tennessee, United States
  • Ibrahim, Atif, The University of Tennessee Health Science Center College of Medicine, Memphis, Tennessee, United States
  • Wall, Barry M., The University of Tennessee Health Science Center College of Medicine, Memphis, Tennessee, United States
  • Kovesdy, Csaba P., The University of Tennessee Health Science Center College of Medicine, Memphis, Tennessee, United States
Background

Severity of CKD is associated with malnutrition and higher risk of death and kidney failure. As a result of the elimination of race from equations estimating GFR (eGFR), the eGFR value of African American patients was revised downward to variable extent, depending on the equation used. It is unclear if the different levels of eGFR and the resultant differences in CKD stages affects the association of kidney function with clinical outcomes such as nutritional status, mortality and ESKD.

Methods

We examined a cohort of 461 African American US veterans with stage 3-5 CKD followed at a single institution. We used the original CKD-EPI equation with and without the inclusion of the race correction factor and the revised 2021 race-free CKD EPI formula to estimate GFR and to determine CKD stages. We examined the association of the different eGFR values and CKD stages with dietary protein intake (g/day, estimated from spot urine urea nitrogen/creatinine) in linear regression models and with all-cause mortality and ESKD incidence in Cox models.

Results

Patients were 66±11 years old, 96% were male, and 60% were diabetic. The race-free equations yielded lower eGFR values and a higher proportion of patients with more advanced stages of CKD, with the lowest eGFR values seen with the race-free old CKD-EPI equation (Table). There were 154 ESKD events (event rate, 82.3/1000 PY; 95%CI, 70.3-96.3) and 250 deaths (133.6/1000PY, 95%CI: 118.0-151.2) over a median follow-up of 4.0 years. Lower eGFR was associated with lower protein intake and higher risk of death and ESKD irrespective of the eGFR formula (Table).

Conclusion

Elimination of race from the GFR estimation formulas results in lower estimated GFR values and a higher proportion of African American patients categorized into more advanced stages of CKD. While subjective decisions using eGFR cutoffs may be influenced by such differences, the association of eGFR with objective clinical outcomes was similar across the different formulas used to estimate GFR.

 Mean (SD) eGFR value (ml/min/1.73m2)CKD stages 2, 3a, 3b, 4 and 5 (%)Dietary protein intake per 10 ml/min/1.73m2 lower eGFR in g/day (95%CI)Hazard ratio (95%CI) of death (per 10 ml/min/1.73m2 lower eGFR)Hazard ratio (95%CI) of ESKD (per 10 ml/min/1.73m2 lower eGFR)
CKD-EPI 2012 with race34 (15)5/19/31/35/10-1.019 (-1.715, -0.324)1.42 (1.29, 1.57)2.16 (1.86, 2.51)
CKD-EPI 2012 without race29 (13)0/13/29/44/14-1.182 (-1.988, -0.375)1.50 (1.34, 1.69)2.44 (2.05, 2.91
CKD-EPI 202131 (13)2/15/32/39/11-1.138 (-1.900, -0.376)1.46 (1.31, 1.63)2.33 (1.98, 2.75)

Funding

  • Veterans Affairs Support