Neutrophil-to-Lymphocyte Ratio as a Cost-Effective Early Prognostic Marker in Acute ST-Elevation Myocardial Infarction (STEMI)

Background: Acute ST-elevation myocardial infarction (STEMI) is characterized by an intense inflammatory response that significantly influences infarct size, complications, and short-term prognosis. Identifying simple and cost-effective inflammatory markers for early risk stratification is crucial, particularly in resource-limited settings. Objective: To evaluate the prognostic significance of the neutrophil-to-lymphocyte ratio (NLR) in patients with acute STEMI and to assess its association with clinical severity, TIMI risk score, Killip class, and in-hospital outcomes. Methods: A prospective observational study was performed involving 100 patients with acute STEMI and 100 age- and sex-matched controls. Hematological parameters at admission were recorded, and NLR was calculated. Clinical risk stratification was performed using TIMI score and Killip classification. In-hospital outcomes were documented and analyzed statistically. Results: STEMI patients demonstrated significantly higher neutrophil counts and lower lymphocyte counts, resulting in elevated NLR compared to controls (p < 0.001). NLR showed a strong positive correlation with TIMI risk score and Killip class. Higher NLR values were significantly associated with adverse in-hospital outcomes including cardiogenic shock, reduced left ventricular ejection fraction, ICU admission, complications, and mortality. Conclusion: NLR is a simple, inexpensive, and reliable prognostic marker in acute STEMI. Its strong association with disease severity and adverse outcomes supports its routine use for early risk stratification.