Comparative Study of Systemic Inflammatory Markers in Clinical Phenotypes of Chronic Obstructive Pulmonary Disease

Chronic Obstructive Pulmonary Disease (COPD) is an inflammatory pulmonary disorder with systemic inflammatory manifestations. This study aims to identify the profile of systemic inflammatory markers in the different phenotypes of COPD to help predict the disease and identify suitable treatment options.
A prospective observational study was conducted on 92 patients with COPD admitted to Victoria Hospital, Bangalore between August 2021 to December 2021. Levels of C-reactive protein (CRP), Serum Creatinine, Erythrocyte Sedimentation Rate (ESR), Absolute Lymphocyte Count (ALC), Absolute Eosinophil Count (AEC), and Lactate Dehydrogenase (LDH) were measured within 48 hours of presentation.
Significantly higher levels of CRP were found in frequent exacerbator emphysema and chronic bronchitis phenotypes (p=0.001). The frequent exacerbator emphysema phenotype had significantly higher levels of LDH (p=0.001) and serum creatinine (p=0.001). Not surprisingly, absolute eosinophil counts were significantly raised in the overlap COPD-Asthma phenotype (p=0.001).
Raised serum CRP levels in the frequent exacerbator phenotypes of emphysema and chronic bronchitis suggest a possible inflammatory response to an infective etiology. Raised LDH levels in frequent exacerbator emphysema phenotype could signify underlying lung parenchymal destruction. Systemic inflammation and oxidative stress can lead to skeletal muscle injury and atrophy in COPD patients. This may explain the raised serum creatinine levels in frequent exacerbator emphysema phenotype. Eosinophilia seen in Overlap COPD-Asthma phenotype is suggestive of type 2 inflammation of the airways with better response to steroids.