Assessment of Serum Interleukin-6 Level in Patients with Chronic Obstructive Pulmonary Disease

Abstract

Chronic obstructive pulmonary disease (COPD) is a major global health challenge, particularly in low and middle-income countries. Systemic inflammation plays a central role in COPD pathogenesis, with interleukin-6 (IL-6) implicated as a key inflammatory mediator. This study aimed to determine the association of serum interleukin-6 (IL-6) levels with chronic obstructive pulmonary disease (COPD). This hospital-based case-control study at Dhaka Medical College Hospital, Bangladesh, investigated the association between serum IL-6 levels and COPD, comparing 29 COPD patients and 29 healthy age- sex matched controls. Serum IL-6 levels were measured using enzyme-linked immunosorbent assay (ELISA), and spirometry assessed lung function (FEV1, FVC, FEV1/FVC ratio). The unpaired "t" test was done between two means in the case of descriptive value, and the chi-square test was also done in the categorical variable. The COPD group exhibited significantly higher mean serum IL-6 levels (5.37 pg/ml) compared to controls (2.51 pg/ml; p=0.0002), confirming a strong association with the disease. Spirometric findings revealed severe airflow limitation in COPD patients, with lower FEV1 (31.21% vs. 72.52%, p<0.0001), FVC (2.02 L vs. 2.82 L, p<0.0001), and FEV1/FVC ratio (52.43% vs. 79.64%, p<0.0001). A strong positive correlation (ρ = 0.94) was found between COPD exacerbation count in the last year and serum IL-6 level. Smoking status differed significantly between groups (p=0.0213), reflecting its role as a major COPD risk factor. Serum Interleukin-6 level was significantly higher in COPD patients than healthy controls and correlated with exacerbation frequency. The study highlights the need for integrating IL-6 testing with spirometry for comprehensive COPD assessment in resource-limited settings. Future prospective longitudinal studies should explore IL-6’s temporal dynamics and therapeutic potential.