Associations between different eGFR estimating equations and mortality for CVD patients: A retrospective cohort study based on the NHANES database

To assess the associations of eGFR(CKD-EPI) (estimated glomerular filtration rate (eGFR) by chronic kidney disease epidemiology collaboration equation), eGFR(MDRD) (eGFR by modification of diet in renal disease), and serum creatinine (scr) on the death for American people diagnosed with cardiovascular disease (CVD) respectively, and to compare the predicted performance of eGFR(CKD-EPI), eGFR(MDRD), and scr. A total of 63,078 participants who derived from the National Health and Nutrition Examination Survey (NHANES) database, were obtained in this retrospective cohort study, and collected the baseline characteristics all participants. The outcomes of our study were defined as death, and eGFR estimating equations was defined as eGFR(CKD-EPI), eGFR(MDRD), and scr. Univariate and multivariate COX analysis were performed to assess the relationship. A subgroup analysis was conducted based on whether patients had anemia. Simultaneously, we also considered the predictive value of eGFR(CKD-EPI), eGFR(MDRD), and scr in the risk of death. All patients were followed for at most 5-years. After excluded participants who did not meet the inclusion criteria and had missing information, the present study included 2419 participants ultimately, and were divided into alive group (n = 1800) and dead group (n = 619). The mortality rate for CVD patients in this study was approximately 25.59% at the end of follow-up. After adjustment for covariates, the result showed that participants with eGFR(CKD-EPI)/eGFR(MDRD) < 30 mL/min/1.73 m(2) or 30 to 45 mL/min/1.73 m(2) had a higher risk of mortality. Similarly, participants with scr (Q4 ≥ 1.2) were associated with the increased risk of death. Additionally, eGFR(CKD-EPI) has a higher predictive value in 1-year, 3-years, and 5-years risk of death among patients with CVD than eGFR(MDRD) and scr. The lower level of eGFR was associated with higher risk of death among American population diagnosed with CVD, especially for non-anemic patients. Importantly, our study also displayed that CKD-EPI-based calculation equation of eGFR (eGFR(CKD-EPI)) provided for a better predictive value than eGFR(MDRD) and scr in the risk of death.