Routine blood test biomarkers and their association with exacerbations in COPD

Introduction: Chronic obstructive pulmonary disease is associated with increased lung and systemic inflammation. As part of a multicenter, international study, we aimed to identify associations between easy-to-obtain blood biomarkers and frequency and severity of exacerbations. Methods: Cross-sectional and multicentre study performed in four centers in Spain, Italy, Bulgaria and Slovenia. Patients with COPD according to GOLD criteria were included and blood samples were obtained for blood cells, C-reactive protein (CRP), alpha-1 antitrypsin and fibrinogen. A multivariate stepwise logistic regression model was performed to identify laboratory parameters associated with history of exacerbations. Results: A total of 355 patients were included (mean age 66 years (SD=8.9) and 64% male). Mean FEV1% was 55% (SD=20%) and mean CAT 15.6 (SD=7.9). 208 patients presented ≥1 exacerbation in the previous year, of them 121 (58%) required hospitalization. Patients with exacerbations had only higher CRP (p=0.007), but those with hospitalizations had a higher platelet count (p=0.031) and platelet/lymphocyte ratio (p=0.031), lower hemoglobin (p=0.017) and lower eosinophil/basophil ratio (p= 0.013). Neutrophil to lymphocyte ratio was also higher but not significantly. However, in multivariate analysis only lower FEV1% was identified as independently related to previous exacerbations (OR=0.970, p=0.012). Conclusion: Only CRP was higher in patients with exacerbations, but several routine blood biomarkers were significantly increased in patients who suffered hospital admissions. However, multivariate analysis identified FEV1 as the only significantly associated variable to previous exacerbations.