#3619 CKD EPI 2021 EQUATION FOR EGFR HAS GOOD EFFICACY TO PREDICT CLINICAL OUTCOMES IN A LARGE PROSPECTIVE COHORT OF ADULT KOREANS
Authors: Chin Ho Jun , Na Ki Young 
Published: June 2023

Abstract

Background and Aims
A new eGFR equation using serum creatinine (CKD-EPI 2021) without race were developed by Chronic Kidney Disease Epidemiology Collaboration in 2021. We projected the changes of eGFR, CKD prevalence, and incidence of end stage renal disease (ESRD) and mortality in a large prospective cohort of adult Koreans who had voluntary health check-ups, using current (CKD-EPI 2009) and new equation (CKD-EPI 2021).

Method
We included 112,772 adult participants, aged 18 years or older, who had voluntary routine health check-ups including serum creatinine at three medical centers in Korea from 2003 to 2009. We compared the difference of eGFR and predictability of mortality and ESRD between eGFR values calculated by CKD-EPI 2009 and CKD-EPI 2021. Serum creatinine was expressed as the IDMS-traceable creatinine according to the manufacturer's conversion formula from the original value measured by the alkaline picrate Jaffe kinetic method. The incidence of mortality data was extracted from Statistics Korea and the ESRD data from the ESRD registry of the Korean Society of Nephrology.

Results
At baseline study, there were 60,723 males (53.8%). Age was 48.9 ± 12.0 years. The value of IDMS-traceable serum creatinine was 0.86 ± 0.21 mg/dl. Levels of eGFR at baseline study were 93.5 ± 15.6 ml/min/1.73 m2 by CKD-EPI2009, and 97.1 ± 15.0 ml/min/1.73 m2 by CKD-EPI2021. Values subtracted eGFRs by CKD-EPI2009 from eGFR by CKD-EPEI2021 were 3.6 ± 1.2 (range: -32.9∼6.1) ml/min/1.73 m2. The difference of eGFR was higher in males compared to females (p&lt;0.001), was the highest in the oldest group among patients aged 18–44 years, 45–64 years, and 65 years or more (p&lt;0.001). Patients with diabetes mellitus (DM) or hypertension showed higher difference of eGFR compared patients without DM or hypertension, respectively (each p&lt;0.001). Patients with eGFR ≥120.0 ml/min/1.73 m2 by CKD-EPI 2009 showed the highest difference between two eGFRs compared to patients with the other values. CKD stage was improved in 11,828 (10.5%) participants using eGFR calculated by CKD-EPI 2021 instead of CKD-EPI 2009, however, only 0.63% of participants with eGFR &lt;60 ml/min/1.73 m2 by CKD-EPI equation was reclassified into eGFR ≥60 ml/min/1.73 m2 by CKD-EPI 2021.During 11.6 ± 2.0 years, 3354 (3.00%) subjects were dead and 151 (0.13%) subjects had end stage renal disease (ESRD) before death. Any eGFR or stage of eGFR was an independent risk factors to ESRD or mortality estimated by Cox's hazard proportional model adjusted by related factors. AUC to estimate renal survival by eGFRs was not different between eGFRs by CKD-EPI2021 and CKD-EPI2009 [0.739 (0.687-0.790) vs 0.740(0.688-0.792), p = 0.170]. p&lt;0.001]. AUC to estimate survival by eGFRs calculated through CKD-EPI equation was slightly higher than that by CKD-EPI2021 equation [0.673(0.664-0.682) vs 0.667(0.658-0.676), p&lt;0.001], however, the difference of AUC was negligible [standard error of AUC difference by two eGFRs; 0.96 (95% CI; 0.006-0.007)].

Conclusion
The eGFR calculated by CKD-EPI2021 was higher compared to eGFR calculated by CKD-EPI2009. The power to estimate renal survival was not different between eGFRs by CKD-EPI2021 and CKD-EPI2009.