Blood eosinophil count and treatment patterns of chronic obstructive pulmonary disease patients in South Korea using real-world data

Background/Aims: Chronic obstructive pulmonary disease (COPD) management guidelines have increasingly emphasised the importance of exacerbation prevention, and the role of blood eosinophil count (BEC) as a biomarker for inhaled cortico-steroids (ICS) response. This study aimed to describe the distribution and stability of BEC and understand real-world treatment patterns among COPD patients in South Korea. Methods: This was a retrospective database analysis using data obtained from the KOrea COPD Subgroup Study (KOCOSS) registry between January 2012 and August 2018. KOCOSS is an ongoing, longitudinal, prospective, multi-centre, non-in-terventional study investigating early COPD amongst South Korean patients. BEC stability was assessed by calculating the intra-class correlation (ICC) coefficient. “Exacerbators” were patients who had a record of ≥ 1 exacerbation in the 12 months prior to the visit. Results: The study included 2,661 patients with a mean age of 68.6 years. Most patients were male (92.0%). Mean BEC was significantly higher in exacerbators compared to non-exacerbators. Patients with ≥ 2 exacerbations at baseline had a less stable BEC over time (ICC = 0.44) compared to non-exacerbators (ICC = 0.57). Patients with BEC ≥ 300 cells/μL at baseline predominantly received triple therapy (43.8%). Conclusions: This study may further develop current understanding on BEC profiles amongst COPD patients in South Ko-rea. BEC measurements are stable and reproducible among COPD patients, which supports its use as a potential biomarker.