Incremental Prognostic Value of Cystatin C-Based Estimated Glomerular Filtration Rate in Patients With Acute Coronary...

The 2021 Chronic Kidney Disease Epidemiology Collaboration (CKD-EPI) equation, which incorporates both creatinine and cystatin C, provides enhanced estimation of glomerular filtration rate (eGFR) compared to creatinine-only equations. This study aimed to explore the incremental prognostic value of eGFR estimates in patients with acute coronary syndrome (ACS).

This retrospective analysis evaluated 1400 ACS patients undergoing a percutaneous coronary intervention (PCI). The primary endpoint was defined as major adverse cardiovascular events (MACEs), a composite of all-cause death and nonfatal myocardial infarction (MI). The eGFR values were calculated using three equations: one based solely on serum creatinine (eGFR_cr), another based only on cystatin C (eGFR_cys), and a combined equation using both creatinine and cystatin C (eGFR_cys-cr). Cox regression and the Kaplan-Meier analyses were employed to identify predictors of MACEs. The incremental prognostic value of the three eGFR equations on ACS outcomes was individually assessed.

Over a median follow-up of 31.03 (27.34, 35.06) months, 135 (9.6%) patients experienced MACEs, including 99 (7.1%) deaths and 41 (2.9%) MIs. Lower eGFR values correlated with higher MACEs and the risk of death. Incorporating eGFR_cys or eGFR_cys-cr into the established risk model improved the predictive accuracy for MACEs. When compared to eGFR_cr, eGFR_cys-cr demonstrated greater capacity to reclassify the risk for MACEs (category-free continuous net reclassification improvement (cNRI)^>0: 0.205 (0.011-0.397); p = 0.03; integrated discrimination improvement (IDI): 0.010 (0.002-0.019); p = 0.01), whereas eGFR_cys did not demonstrate a similar effect.

The eGFR based on the 2021 CKD-EPI equation using both creatinine and cystatin C significantly improves risk prediction and reclassification in ACS patients compared with a creatinine-based equation.