Estimated GFR in the Korean and US Asian Populations Using the 2021 Creatinine-Based GFR Estimating Equation Without Race

Rationale & Objective

In 2021, the new Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) updated the creatinine-based estimated glomerular filtration rate (eGFR) equation and removed the coefficient for race. The development and validation of this equation involved binarizing race into African American and non-African American, involving few Asian participants. This study aimed to examine the difference between the 2021 equation and the previous 2009 equation on CKD prevalence estimates in 2 Asian populations.

Study Design

Observational study using 2 national surveys.

Setting & Participants

Participants from the 2019 Korea National Health and Nutrition Survey and participants self-reported as Asian from the 2011-2020 US National Health and Nutrition Survey.

Exposure

eGFR using 2009 and 2021 CKD-EPI creatinine equation.

Outcomes

Prevalence of CKD (eGFR <60 mL/min/1.73 m² or urine albumin-creatinine ratio ≥30 mg/g).

Analytical Approach

Sampling-weighted prevalence estimated using the 2009 and 2021 equations as well as the percentage of individuals with CKD G3+ using the 2009 equation being reclassified as not having CKD G3+ using the 2021 equation.

Results

The prevalence of CKD estimated using the 2021 equation was 9.75% (95% confidence intervals [CI], 8.80-10.80%) in Koreans and 11.60% (95% CI, 10.23-13.13%) in US Asians. The prevalence of CKD estimated using the 2021 equation was slightly lower than that using the 2009 equation in both Korean and US Asian populations by 0.63% (95% CI, 0.44-0.90%) and 0.84% (95% CI, 0.52-1.34%), respectively. Furthermore, 32.8% and 30.2% of Koreans and US Asians with CKD G3-5, respectively, estimated using the 2009 equation were reclassified as not having CKD G3-5 when the eGFR was calculated using the 2021 equation.

Limitations

Measured GFR was not available.

Conclusions

Use of the 2021 CKD-EPI creatinine equation leads to a small decrease in CKD prevalence in both Korean and US Asian populations, and of similar magnitude, resulting in significant reclassification among those originally classified as having CKD G3+.

Plain-Language Summary

The 2009 serum creatinine-based kidney function estimating equation used demographic information including race. Because race is a social construct, race was eliminated in the new equation developed in 2021. As race was categorized into African American and non-African American during its development, this study examined the impact of the 2021 equation in 2 distinct Asian populations (Koreans and US Asians) using 2 national datasets. We found that the prevalence of chronic kidney disease (CKD) estimated using the 2021 equation was slightly lower that estimated using the 2009 equation in both Koreans and US Asians. Approximately one-third of people with CKD estimated using the 2009 equation were reclassified as not having CKD estimated using the 2021 equation.