Abstract
Introduction: We intended to compare the predictive value for all-cause and cardiovascular deaths between estimated glomerular filtration rate (eGFR) derived from the European Kidney Function Consortium (EKFC) cystatin C-based formula, the EKFC creatinine-based formula, and Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) cystatin C- or creatinine-based formulas. Methods: Overall, 4,132 participants from the National Health and Nutrition Examination Survey between 1999 and 2002 were included, and death information was obtained through the National Death Index. To compare predictive accuracy between EKFC eGFRcys (EKFC cystatin C-based formula), CKD-EPI eGFRcys (CKD-EPI cystatin C-based formula), EKFC eGFRcr (EKFC creatinine-based formula), and CKD-EPI eGFRcr (CKD-EPI creatinine-based formula), we conducted time-dependent receiver operator characteristic (ROC) curves and reclassification analysis. Results: During a median follow-up of 17.4 years, a total of 1,987 all-cause and 530 cardiovascular deaths were confirmed. Restricted cubic splines analyses showed that reduced EKFC eGFRcys was linearly related to higher risks of all-cause and cardiovascular deaths (p for nonlinearity > 0.05). Time-dependent ROC curves suggested that EKFC eGFRcys exhibited higher predictive ability than CKD-EPI eGFRcys, EKFC eGFRcr, and CKD-EPI eGFRcr at 5-year and 10-year follow-ups. For 10-year all-cause deaths, EKFC eGFRcys yielded significant improvement over CKD-EPI eGFRcr (integrated discrimination improvement [IDI], 9.4%; net reclassification improvement [NRI], 39.7%). Similar improvement was observed in 10-year cardiovascular deaths when comparing EKFC eGFRcys to CKD-EPI eGFRcr (IDI, 6.7%; NRI, 45.1%). Conclusion: The EKFC eGFRcys outperformed CKD-EPI eGFRcys, EKFC eGFRcr, and CKD-EPI eGFRcr in predicting all-cause and cardiovascular deaths, providing the possibility to utilize EKFC eGFRcys in the stratification of death risk among the general US population.
Plain Language Summary
Our study demonstrated the superiority of the European Kidney Function Consortium. (EKFC) cystatin C-based formula in predicting the risk of all-cause and cardiovascular deaths compared with the Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) cystatin C-based, EKFC creatinine-based, or CKD-EPI creatinine-based formulas in the general US population. Our finding confirmed a linear and negative relationship between the estimated glomerular filtration rate (eGFR) derived from the EKFC cystatin C-based formula and the risk of all-cause and cardiovascular deaths. The EKFC cystatin C-based formula exhibited a higher predictive ability for the risk of all-cause and cardiovascular deaths than the CKD-EPI cystatin C-based, EKFC creatinine-based, or CKD-EPI creatinine-based formulas.
