Correlation between CAT score, inflammatory markers and pulmonary function tests in patient with acute exacerbation of COPD

Gaining insights into chronic obstructive pulmonary disease exacerbation through emerging biomarkers and the chronic obstructive pulmonary disease assessment test score

Chronic obstructive pulmonary disease (COPD), a leading cause of mortality and morbidity, presents significant challenges, particularly with exacerbations, which drastically impact patients' health and healthcare costs. The Global Initiative for Chronic Obstructive Lung Disease guidelines recommend comprehensive assessments beyond spirometry, with the COPD assessment test (CAT) emerging as a pivotal tool. Despite its utility, the relationship between CAT scores and specific biomarkers during exacerbations remains unclear. Hence, this study aims to assess the correlation between the CAT score and specific circulating biomarkers. A cross-sectional study from August 2023 to January 2024 included 59 COPD patients with exacerbations who underwent pulmonary function tests and completed the CAT score assessment. The CAT score cut-off point was set at 20, where a CAT score <20 indicated a low impact on health status and a CAT score ≥20 indicated a high impact on health status. On the same day, measurements of neutrophils, leukocytes, eosinophils, C-reactive protein, and procalcitonin were conducted. Patients with CAT scores ≥20 had significantly higher levels of neutrophils (p=0.001), leukocytes (p=0.006), procalcitonin (p=0.010), and forced expiratory volume in the first second/forced vital capacity (p=0.002), but lower eosinophil levels (p=0.025). A positive correlation existed between total CAT score and neutrophils (p=0.001), leukocytes (p=0.000), and procalcitonin (p=0.010), while eosinophil levels showed a negative correlation (p=0.025). The spirometry parameters showed no correlation with the total CAT score. This study highlights the link between CAT and key inflammatory biomarkers, supporting the use of blood biomarkers to identify COPD patients at risk of exacerbations.