Background: The neutrophil to lymphocyte ratio (NLR) is an inflammatory biomarker that could be used as an indicator of systemic inflammation (sepsis) and could also be used to predict the prognosis of some diseases, such as solid cancer, community pneumonia, as well as cardiovascular diseases. This study aimed to assess the potential role of NLR and eosinopenia in patients with acute exacerbation of COPD (AECOPD) compared to those in the stable phase of the disease.
Materials and Methods: NLR was assessed and compared in patients with AECOPD (n=92) and those in the stable phase of COPD (n=240). Patients under the age of 18, those who used inhaled corticosteroids, or those with any condition affecting the neutrophil (NEU) or lymphocyte (LYM) count in peripheral blood, such as hematological illnesses, pregnancy, or a history of medication use, were excluded from the study. The NLR was determined using NEU and LYM counts from regular blood tests. We defined the cut-off value for eosinopenia as the percentage of eosinophils≤1%.
Results: We included 332 inpatients with COPD diagnosed in our hospital from April to October 2021.  AECOPD was discovered in 92 patients. Patients with exacerbation had considerably lower levels of BMI (24.32±4.38 vs 26±4.02), FEV1/FVC (55.38±9.14 vs 60.54±6.95), and NLR ratio, except for the first NLR quartile (39.13 %), the second was 20.65 %, the third was 18.48 %, and the fourth was 21.74 %. Eosinopenia was detected in 79 (85.87 %) of AECOPD patients.
Conclusion: We found that the NLR was lower in patients with Acute Exacerbation of Chronic Obstructive Pulmonary Disease (AECOPD), except for those in the first NLR quartile.