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Kidney Week

Abstract: PO2316

Reduced Differences in Clinical Outcomes Between Black and White Veterans with Incident CKD After Removal of Race from Estimated Glomerular Filtration Rate (eGFR)

Session Information

Category: CKD (Non-Dialysis)

  • 2102 CKD (Non-Dialysis): Clinical, Outcomes, and Trials

Authors

  • Yan, Guofen, University of Virginia School of Medicine, Charlottesville, Virginia, United States
  • Norris, Keith C., University of California Los Angeles David Geffen School of Medicine, Los Angeles, California, United States
  • Nee, Robert, Walter Reed National Military Medical Center, Bethesda, Maryland, United States
  • Scialla, Julia J., University of Virginia School of Medicine, Charlottesville, Virginia, United States
  • Yu, Wei, University of Virginia School of Medicine, Charlottesville, Virginia, United States
  • Greene, Tom, University of Utah Health, Salt Lake City, Utah, United States
  • Cheung, Alfred K., University of Utah Health, Salt Lake City, Utah, United States
Background

Assessing outcomes for racial subgroups can guide strategies to mitigate health and healthcare inequalities. We assessed differences in clinical outcomes by Black and White race following incidence of CKD defined when eGFR was computed with and without a race coefficient.

Methods

The study population was veterans, either non-Hispanic White or non-Hispanic Black, in the US Veterans Health Administration who had incident CKD stage G3 or higher (i.e., first eGFR<60 mL/min/1.73 m2 for >3 months) between 2007 and 2016. eGFR values were calculated first using the Chronic Kidney Disease Epidemiology Collaboration equation (CKD-EPI) with its race term included and again using the same equation without the race coefficient (CKD-EPI-RACEout). We examined risks of initiating kidney replacement therapy (KRT) and death in Blacks and Whites, with follow-up from incident CKD until May 31, 2018 or up to 10 years.

Results

115,374 Black veterans had incident CKD defined by CKD-EPI-RACEout vs. 84,090 by CKD-EPI; and 507,303 White veterans by CKD-EPI, with mean ages at CKD incidence of 64, 67 and 73 years, respectively. Blacks with CKD defined by CKD-EPI-RACEout had lower rates of both KRT and death (8.2 and 44.8 per 1000 patient-years, respectively) compared with Blacks by CKD-EPI (Table). After adjustment for age, sex, eGFR at CKD incidence, and CKD incidence year, Blacks by CKD-EPI-RACEout had a 41% greater risk of KRT than Whites, a markedly decrease from the 172% greater risk with CKD-EPI. Also, Blacks by CKD-EPI-RACEout had a 7% lower risk of death than Whites, in contrast to a 10% greater risk of death with CKD-EPI.

Conclusion

Compared to Whites, Blacks with incident CKD defined by CKD-EPI eGFR without the race coefficient remained more likely to develop KRT, though the relative risk was greatly attenuated; conversely, they had slightly longer survival after case-mix adjustment. Different methods of accounting for race in GFR estimation would affect measures of health outcome disparities in CKD.

Hazard ratios of outcomes for Black versus White veterans with incident CKD
 Kidney replacement therapy (KRT)Death
Event rate
(per 1000 patient-years)
Unadjusted hazard ratio (95% CI)Adjusted hazard ratio (95% CI) (age, sex, eGFR and incident-year)Event rate
(per 1000 patient-years)
Unadjusted hazard ratio (95% CI)Adjusted hazard ratio (95% CI) (age, sex, eGFR and incident-year)
Black, identified by CKD-EPI without race coefficient8.22.42
(2.33-2.51)
1.41
(1.36-1.46)
44.80.60
(0.59-0.61)
0.93
(0.92-0.94)
Black,
identified by CKD-EPI
15.24.56
(4.40-4.71)
2.72
(2.62-2.82)
62.90.85
(0.84-0.86)
1.10
(1.09-1.12)
White3.41174.311

Funding

  • NIDDK Support