Comparison of low eGFR prevalence and prediction for mortality using 2009 and 2021 CKD-EPI equations in Mexican adults

Accurate estimation of glomerular filtration rate (eGFR) is essential for identifying and managing chronic kidney disease (CKD). The CKD-EPI 2021 equation removed the race coefficient from the 2009 version, but its impact in Mexican populations remains unclear. Here, we compared eGFR category prevalence, and predictive performance between the CKD-EPI 2009 and 2021 creatinine-based eGFR equations, as well as the prognostic relevance of reclassification in eGFR categories using the 2021 equation in Mexicans. We evaluated 25,110 adults _≥ 20 years from the 2016-2023 cycles of the Mexican National Health and Nutrition Survey (ENSANUT) to estimate national low eGFR and eGFR category prevalence using both equations. We also assessed 5-year and 10-year risk of all-cause, cardiovascular, and kidney-related mortality in 142,884 adults from the Mexico City Prospective Study (MCPS) using Cox proportional hazards and Fine & Gray regression models. In ENSANUT 2023, prevalence of eGFR <60mL/min/1.73m2 was lower with CKD-EPI 2021 (2.9%, 95%CI 1.56–4.24%) compared to the 2009 equation (3.6%, 95%CI 1.99–5.21). Use of the 2021 equation resulted in upward eGFR reclassification in 6.52% (95%CI 4.07-8.97) of adults _≥ 20 years, particularly among older adults and those with hypertension or diabetes, yielding a reduction in 486,532 adults identified with eGFR <60mL/min/1.73m ² compared to the 2009 equation. In MCPS, despite both equations showing similar C-statistics, the 2021 equation showed slightly improved predictive performance for 5-year and 10-year mortality outcomes. The 2021 equation reclassified 8.3% of participants to higher eGFR categories, and reclassification was associated with decreased risk of all-cause, cardiovascular, and kidney-related mortality, particularly for participants reclassified upward from G3a-G5 categories. The CKD-EPI 2021 equation yields lower prevalence of low eGFR but leads to prognostically relevant eGFR category reclassification compared to the 2009 equation. Our findings support the implementation of the 2021 equation for population health monitoring in Mexico without compromising prognostic utility.