Prognostic Value of Baseline Neutrophil-to-Lymphocyte Ratio Combined With Anemia in Patients With ST-Segment Elevation Myocardial Infarction: A Nationwide Prospective Cohort Study

OBJECTIVE: Data pertaining to the prognostic value of the combination of high neutrophil-to-lymphocyte ratio (NLR) and anemia on admission in patients with ST-segment elevation myocardial infarction (STEMI) are limited. The objective of this study was to investigate the clinical value of baseline NLR in combination with anemia in predicting clinical outcomes after STEMI. METHODS: A total of 5,194 consecutive patients with STEMI within 12 hours of symptom onset from the Korea Acute Myocardial Infarction Registry-National Institute of Health database between 2011 and 2015 were categorized into 4 groups according to their NLR and hemoglobin levels: low NLR (<4) without anemia (n=2,722; reference group); high NLR (≥4) without anemia (n=1,527); low NLR with anemia (n=508); and high NLR with anemia (n=437). The co-primary outcomes were 180-day and 3-year all-cause mortality. RESULTS: Mortality rates significantly increased at the 3-year follow-up across the groups (3.3% vs. 5.4% vs. 16.5% vs. 21.7% for 180-day mortality and 5.3% vs. 9.0% vs. 23.8% vs. 33.4% for 3-year mortality; all p-trends <0.001). After adjusting for baseline covariates, the combination of high NLR and anemia was a significant predictor of 180-day mortality after STEMI with low NLR and no anemia as the reference (adjusted hazard ratio, 2.16; 95% confidence interval, 1.58–2.95; p<0.001). Similar findings were observed for the 3-year mortality. CONCLUSIONS: This nationwide prospective cohort study showed that the combination of high NLR (≥4) and anemia is a strong predictor of all-cause mortality after STEMI.