Summary: | 碩士 === 國立中山大學 === 生物科學系研究所 === 106 === Background: Chronic obstructive pulmonary disease (COPD), the fourth leading cause of death in the world, is a chronic inflammatory disease of the airway characterized by “persistent airflow limitation that is usually progressive”. COPD is recognized as a complex and heterogeneous syndrome. Significant heterogeneity exists within COPD with respect to clinical presentation, physiology, imaging, response to therapy, decline in lung function, and survival. Currently, there are neither consensus phenotypes classification nor useful biomarkers in COPD. Serum IgE and blood eosinophil, which are easy to measure, have been used as biomarkers in asthma. This study aimed to evaluate the clinical utility of serum IgE levels and blood eosinophil counts in COPD patients.
Methods: We conducted a prospective observational study in Kaohsiung Medical University Hospital. From Jan 1, 2016 to Dec 31, 2017, we enrolled 208 patients with COPD into this study. These patients were followed till Mar 31, 2018, with a mean follow-up period of 18.8 months. Of the 208 enrolled patients, 190 with complete data were analyzed. We compared clinical features and exacerbation frequency between COPD patients with serum IgE < 100 KU/L vs. ≥ 100 KU/L, blood eosinophil counts < 300/µL vs. ≥ 300/µL and blood eosinophil < 4% vs. ≥ 4%
Results: Of the 190 COPD patients analyzed in this study, 56 (29.5%) patients had moderate or severe acute exacerbation events, 55 (28.9%) had blood eosinophil ≥ 300/µL, 65 (34.2%) had blood eosinophil ≥ 4%, and 83 (45.1%) had serum IgE ≥ 100 KU/L. COPD patients with blood eosinophil ≥ 300/µL or > 4% had significantly higher risk of acute exacerbation (OR = 2.80, 95% CI = 1.44-5.44, P = 0.011; OR = 2.35, 95% CI = 1.23-4.48, P = 0.093). Serum IgE ≥ 100 KU/L were not associated with higher risk of acute exacerbation (OR = 0.81, 95% CI = 0.43-1.55, P = 0.533). In multivariate analysis, positive bronchodilator response, diffusion capacity of the lung for carbon monoxide (DLCO) and blood eosinophil percentage were significantly associated with acute exacerbation risk. For every 1% increment in blood eosinophil, the risk of exacerbation increased by 25% (OR = 1.25, 95% CI = 1.09-1.43, P = 0.001).
Conclusion: Blood eosinophil count and percentage were significantly associated with acute exacerbation in COPD. For every 1% increment in blood eosinophil, the risk of exacerbation increased by 25%. Serum IgE levels were not associated with risk of COPD acute exacerbation. Blood eosinophil are easily available and can serve as useful biomarkers in COPD. We suggest measuring blood eosinophil counts or percentage routinely in COPD to evaluate the risk of future acute exacerbation.
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