Burden of disease in COPD, stratified by eosinophils levels: a UK biobank study

Evidence suggests that blood eosinophil levels (EOS) can influence response to therapy in COPD. This study's objective is to characterize the COPD burden and resource use, stratified by EOS levels. COPD patients were retrieved from the UK biobank, a population-based prospective cohort of 500,000 adults, aged 40-70 recruited between 2006-10 and followed until Dec-2019. Differences in the prevalence of atopic comorbidities at baseline and in yearly mortality rate, all-cause hospitalizations and GP visits during follow-up were assessed. Incidence of severe exacerbations was analyzed by multivariate logistic regressions, and confounders were added by stepwise variable selection. 5,097 COPD patients were followed for 9.9 years (±2.5). The 1,022 (20%) patients with EOS≥300 were older (61.8 vs. 61.3years), had a higher prevalence of males (65 vs 53%), a higher BMI (28.2 vs 27.8), and a higher smoking prevalence (31 vs 27%), than patients EOS<300. Air pollution exposure prevalence was similar. The prevalence of atopic comorbidities (atopic dermatitis, chronic rhinosinusitis with/without polyp, and allergic rhinitis) at baseline was higher in patients with EOS≥300 (10 vs 7%). During the follow-up period, no statistically significant differences were observed in yearly mortality rate, GP visits, and all-cause hospitalizations. EOS≥300 was significantly associated with having 1 or more severe exacerbation during the follow-up period, after controlling for sociodemographic characteristics, smoking status, and atopic comorbidities (adjusted OR=1.20 [95%CI 1.03-1.39], p=0.021). COPD patients with EOS≥300 have more comorbid atopic conditions and experience more frequent severe exacerbations than patients with EOS<300.