The Role of Neutrophil to Lymphocyte Ratio in Predicting Clinical Outcomes in Chronic Obstructive Pulmonary Disease Patients: A Single-Center Cohort Study

Introduction: The primary objective of the study was to scrutinize the neutrophil to lymphocyte ratio (NLR) in patients afflicted with chronic obstructive pulmonary disease (COPD).Methods: This study, conducted at Mashhad University of Medical Sciences in Iran between 2021-2022, aimed to analyze the NLR. Data were collected from medical records, laboratory reports, and personal interviews, focusing on demographic data, clinical histories, and various laboratory and clinical parameters. The severity of COPD was assessed using several clinical scales and spirometry measurements. Statistical analysis was performed using SPSS and R software.Results: In this study, a cohort of 49 patients with COPD was analyzed, with a majority being male (59%) and having an average age of 62.3 years. The mean NLR was 2.1. The correlation analysis showed a moderate negative correlation between Ejection Fraction and NLR (rho = -0.30, p = 0.03), and a weak positive correlation between Erythrocyte Sedimentation Rate and NLR (rho = 0.28, p = 0.04). Comparative analysis of NLR with COPD clinical scales showed a significant rise in NLR from category 0 to 2 in AECOPD cases (p=0.04). Concurrent ROC analysis indicates a diagnostic power of 0.68, establishing an NLR cutoff value of 1.67, with a sensitivity of 0.67 and a specificity of 0.71.Conclusions: NLR may serve as a marker for mild to moderate exacerbations in COPD patients (categories 1 and 2); however, its predictive value for severe exacerbations (category 3) remains unclear. Further research is needed to explore the underlying mechanisms and its utility across the full spectrum of exacerbation severity.