Association between the hemoglobin-to-red cell distribution width ratio and short- and long-term mortality in patients with acute myocardial infarction

Accurate long-term risk stratification after acute myocardial infarction (AMI) remains challenging. The hemoglobin-to–red cell distribution width ratio (HRR), derived from routine laboratory parameters, has emerged as a potential integrative prognostic marker, but its value in AMI has not been well established. We conducted a retrospective cohort study of patients hospitalized with AMI at a tertiary medical center between 2016 and 2021. HRR was calculated from the first available hemoglobin and red cell distribution width (RDW) measurements within 2 days of the index diagnosis and categorized into quartiles. The primary outcome was cumulative 3-year all-cause mortality from admission; secondary outcomes included 30-day and 1-year all-cause mortality, and cardiovascular mortality at all three horizons. Discrimination was compared among HRR, hemoglobin, RDW, neutrophil-to-lymphocyte ratio (NLR), and troponin I using receiver operating characteristic analysis and the DeLong test. The GRACE post-discharge score was included as an exploratory comparator outside its original post-discharge setting. Kaplan–Meier analysis and multivariable Cox regression were used; the latter considered demographic, clinical, and laboratory variables and in-hospital PCI and transfusion. Among 2,498 patients (807 ST-elevation myocardial infarction and 1,691 non-ST-elevation myocardial infarction), median HRR was 0.931 (interquartile range 0.714–1.125). Within 3 years of the index admission, 891 patients (35.7%) died, including 409 cardiovascular-related deaths. For 3-year all-cause mortality, HRR had the highest AUC among individual biomarkers (0.763, 95% CI 0.744–0.782), exceeding hemoglobin, RDW, NLR, and troponin I (all P < 0.001). In the exploratory comparison, no statistically significant AUC difference was observed versus the GRACE post-discharge score (AUC 0.782; P = 0.063). Compared with the highest HRR quartile, the lowest quartile was associated with higher 1-year (aHR 1.90, 95% CI 1.31–2.75) and 3-year (aHR 2.33, 95% CI 1.70–3.19) all-cause mortality. Associations with 30-day all-cause mortality and cardiovascular mortality were not statistically significant after multivariable adjustment. Lower HRR was associated with increased cumulative 1-year and 3-year all-cause mortality from the index AMI admission in the fitted multivariable models. HRR warrants further evaluation as a readily available prognostic marker, including assessment of incremental value over established risk scores. Not applicable.