Prediction of End-Stage Kidney Disease Using Estimated Glomerular Filtration Rate With and Without Race : A Prospective Cohort Study

Abstract

Background: New estimated glomerular filtration rate (eGFR) equations removed race adjustment, but the impact of its removal on prediction of end-stage kidney disease (ESKD) is unknown.

Objective: To compare the ESKD prediction performance of different eGFR equations.

Design: Observational, prospective cohort study.

Setting: 7 U.S. clinical centers.

Participants: 3873 participants with chronic kidney disease (CKD) from the CRIC (Chronic Renal Insufficiency Cohort) Study contributing 13 902 two-year risk periods.

Measurements: ESKD was defined as initiation of dialysis or transplantation. eGFR was calculated using 5 Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equations based on serum creatinine and/or cystatin C, with or without race adjustment. The predicted 2-year risk for ESKD was calculated using the 4-variable Kidney Failure Risk Equation (KFRE). We evaluated the prediction performance of eGFR equations and the KFRE score using discrimination and calibration analyses.

Results: During a maximum 16 years of follow-up, 856 participants developed ESKD. Across all eGFR equations, the KFRE score was superior for predicting 2-year incidence of ESKD compared with eGFR alone (area under the curve ranges, 0.945 to 0.954 vs. 0.900 to 0.927). Prediction performance of KFRE scores using different eGFR equations was similar, but the creatinine equation without race adjustment improved calibration among Black participants. Among all participants, compared with an eGFR less than 20 mL/min/1.73 m², a KFRE score greater than 20% had similar specificity for predicting 2-year ESKD risk (ranges, 0.94 to 0.97 vs. 0.95 to 0.98) but higher sensitivity (ranges, 0.68 to 0.78 vs. 0.42 to 0.66).

Limitation: Data are solely from the United States.

Conclusion: The KFRE score better predicts 2-year risk for ESKD compared with eGFR alone, regardless of race adjustment. The creatinine equation with age and sex may improve calibration among Black patients. A KFRE score greater than 20% showed high specificity and sensitivity for predicting 2-year risk for ESKD.

Primary funding source: National Institutes of Health.

Figure 1.

Discrimination of ESKD Events by eGFR and KFRE Score using Various Equations AUC = area under the receiver operating characteristic curve; CI = confidence interval; CKD-EPI = Chronic Kidney Disease Epidemiology Collaboration; eGFR = estimated glomerular filtration rate; IDI = integrated discrimination improvement; KFRE = Kidney Failure Risk Equation Higher values for AUC indicate better performing models.

Figure 2.. Discrimination and Calibration of ESKD Events by KFRE Score using Various Equations

AUC = area under the receiver operating characteristic curve; CI = confidence interval; KFRE = kidney failure risk equation. Higher values for AUC and scaled Brier score indicate better performing models. A. The AUC (95% CI) among Black participants is 0.951 (0.941-0.961) for the creatinine equation with age, sex, and race; 0.951 (0.941-0.961) for the creatinine equation with age and sex; 0.945 (0.936-0.955) for the cystatin C equation with age and sex; 0.953 (0.943-0.962) for the creatinine and cystatin C equation with age, sex, and race; and 0.953 (0.944-0.962) for the creatinine and cystatin C equation with age and sex. B. The AUC (95% CI) among Black participants is 0.954 (0.944-0.962) for the creatinine equation with age, sex, and race; 0.954 (0.944-0.962) for the creatinine equation with age and sex; 0.945 (0.935-0.954) for the cystatin C equation with age and sex; 0.953 (0.943-0.961) for the creatinine and cystatin C equation with age, sex, and race; and 0.953 (0.943-0.961) for the creatinine and cystatin C equation with age and sex. C. The scaled Brier score (95% CI) among Black participants is 0.437 (0.406-0.467) for the creatinine equation with age, sex, and race; 0.451 (0.418-0.480) for the creatinine equation with age and sex; 0.368 (0.337-0.399) for the cystatin C equation with age and sex; 0.427 (0.397-0.457) for the creatinine and cystatin C equation with age, sex, and race; and 0.426 (0.396-0.457) for the creatinine and cystatin C equation with age and sex. D. The scaled Brier score (95% CI) among non-Black participants is 0.419 (0.384-0.449) for the creatinine equation with age, sex, and race; 0.404 (0.369-0.433) for the creatinine equation with age and sex; 0.357 (0.325-0.385) for the cystatin C equation with age and sex; 0.409 (0.375-0.438) for the creatinine and cystatin C equation with age, sex, and race; and 0.396 (0.365-0.426) for the creatinine and cystatin C equation with age and sex.