Neutrophil-to-Lymphocyte Ratio (NLR) Useful as a Cost-Effective Preliminary Prognostic Marker in ST-Elevation Myocardial Infarction (STEMI): An Observational Study From a Tertiary Care Hospital in Northeast India.

Introduction Myocardial infarction, a major consequence of coronary artery disease, is an important cause of in-hospital mortality and morbidity worldwide. Blood neutrophil-to-lymphocyte ratio (NLR) is a novel laboratory marker of systemic inflammation that can predict the severity and mortality in various non-cardiovascular illnesses, including malignancy and infective pathology. We sought to evaluate its potential in predicting the outcome in hospitalized patients with myocardial infarction.  Material and methods The index study was conducted at Silchar Medical College and Hospital from June 1, 2021 to May 31, 2022, with the aim of evaluating the role of NLR in determining the outcomes of ST-elevation myocardial infarction (STEMI). A total of 110 patients fulfilling the requisite criteria and admitted to the cardiology and medicine departments of the hospital with evidence of STEMI were included in the study and evaluated for the relationship of NLR with various outcome variables in STEMI.  Results Out of 110 patients, 69.1% were males. The mean age of the study population was 58.2±15.3 years. The baseline characteristics and risk factors of patients who survived the acute attack of STEMI and those who died from complications of STEMI were similar. Laboratory parameters which correlated with worse outcomes included a higher fasting triglyceride level (173.4 mg vs. 215.6 mg, p < 0.001), a higher blood neutrophil count at baseline, 24 hours and 72 hours (70.1% vs. 69.04%, 66.3% vs. 75.2%, 81.6% vs. 73.8%, p<0.05), a higher NLR value at baseline, 24 hours and 72 hours (2.91 ± 1.13 vs. 3.19 ± 2.32, 2.39 ± 0.74 vs. 5.56 ± 4.11, 5.1 ± 4.38 vs. 3.01 ± 1.02, p < 0.05). Among patients hospitalized with STEMI who had high NLR, had significantly elevated incidence of complications, including a higher acute, left ventricular failure (42.8% vs. 35.9%; p < 0.05) as well as increased risk of mortality (66.7% vs. 33.3%; p < 0.05) compared to low NLR group.  Conclusion NLR can predict the outcome among STEMI patients in terms of morbidity and mortality and correlates with poor left ventricular function. NLR can serve as a potential tool for early identification and efficient triage of STEMI patients during initial presentation to the ED. Its utility is more so in resource-constrained developing countries with limited access to health care. The significant advantage of NLR is its easy accessibility, rapid turnaround time, and inexpensiveness.