Association Between Admission Estimated Glomerular Filtration Rate and Long-Term Mortality in Patients with Acute Myocardial Infarction

Background: Reduced estimated glomerular filtration rate (eGFR) and acute kidney injury (AKI) are common in patients with ST-segment elevation myocardial infarction (STEMI) and adversely influence prognosis. This retrospective cohort study evaluated the association between admission eGFR and one-year mortality following STEMI, accounting for admission AKI and cardiovascular risk factors. Methods: Consecutive adults (n = 2903) admitted with STEMI undergoing primary percutaneous coronary intervention (PCI) at a tertiary center were analyzed, selected from 2949 initially screened patients after excluding those treated conservatively or with thrombolysis (n = 14), those with a final discharge diagnosis other than STEMI (n = 21), and early deaths within 24 h of presentation (n = 11). Admission eGFR was calculated using the 2021 CKD-EPI creatinine equation and categorized into quintiles. The primary outcome was all-cause one-year mortality, assessed using multivariable logistic regression and secondary Kaplan–Meier survival analysis. Results: Both one-year and 30-day crude mortality decreased markedly across increasing eGFR quintiles (p < 0.001), a pattern that was maintained among patients presenting without admission AKI (30-day mortality: Q5 4.4% vs. Q1 0.0%, p < 0.001). In crude analysis, 30-day mortality was 9.1% in the lowest eGFR quintile overall. Multivariable logistic regression identified advancing age (OR 1.05 per year, p < 0.001) and admission AKI (OR 7.07, p < 0.001) as the dominant independent predictors of one-year mortality, whereas individual eGFR quintiles were attenuated after adjustment (global Wald p = 0.047). Conclusions: Lower admission eGFR is significantly associated with one-year mortality after STEMI in crude and unadjusted analyses, but its predictive contribution is substantially attenuated following multivariable adjustment for advancing age and admission AKI, which serve as the dominant prognostic determinants. Rather than acting as a strong isolated independent predictor, admission renal function primarily serves as an indicator of baseline cardiorenal reserve and baseline patient vulnerability.