Variation of neutrophil-lymphocyte ratio across global initiative for chronic obstructive lung disease stages in chronic obstructive pulmonary disease

Abstract

Background: Chronic obstructive pulmonary disease (COPD) is a major cause of morbidity and mortality worldwide, particularly in low- and middle-income countries. As COPD is increasingly recognized as a systemic inflammatory disease, the neutrophil-lymphocyte ratio (NLR) has emerged as a simple and inexpensive inflammatory marker. This study was conducted to assess NLR variation across global initiative for chronic obstructive lung disease (GOLD) stages and evaluate its clinical relevance in relation to COPD severity.

Methods: This hospital-based cross-sectional analytical study included 169 spirometry-confirmed COPD patients aged ≥40 years attending Combined Military Hospital, Dhaka. Sociodemographic, clinical, hematological, biochemical, and pulmonary function data were collected. NLR was calculated from absolute neutrophil and lymphocyte counts, and disease severity was classified according to GOLD staging. Data were analyzed using SPSS version 26, with p<0.05 considered significant.

Results: The mean age was 66.0±8.4 years; 82.0% were male and 74.6% had a smoking history. Most patients were classified as GOLD I (60.9%), followed by GOLD II (26.6%), GOLD III (7.1%), and GOLD IV (5.3%). Mean NLR was 2.7±0.6 and increased progressively from 2.1±0.4 in GOLD I to 4.1±0.8 in GOLD IV. FEV₁% predicted and SpO² declined with increasing severity, while CRP increased. NLR correlated negatively with FEV₁% predicted and FEV₁/FVC ratio and positively with exacerbation frequency, CRP, smoking exposure and disease duration. Higher NLR remained independently associated with smoking burden, exacerbation history, CRP and advanced GOLD stages.

Conclusion: NLR increased significantly with COPD severity and may serve as a simple, inexpensive biomarker for severity assessment and risk stratification.