Historical blood eosinophil levels in adults with and without obstructive airways disease

<bold>Introduction:</bold> Blood eosinophil (EOS) levels are used as a marker of inflammation in obstructive airways disease. <bold>Aims:</bold> To explore levels of blood EOS in individuals above age 35 in the general population, and in individuals with COPD and asthma. <bold>Methods:</bold> All individuals aged 35< and <95 years old with a blood EOS sample taken between 2008 and 2022 were included in the study. Blood EOS >0.3*109/Liter was explored. Blood EOS association with age was explored using generalized additive model. A diagnosis of COPD (ICD10 DJ44) or asthma (ICD10 DJ45), was recorded at any hospital contact. <bold>Results:</bold> A total of 6,9 million blood samples from 2.2 million individuals of which 125,313 had COPD, 98,546 asthma, 36,720 COPD/asthma, and 1,943,542 no obstructive airways diseases were included. The median EOS count was for individuals without obstructive airways disease 0.2[0.1-0.3], COPD 0.3[0.2-0.5], asthma 0.3[0.2-0.5], and 0.4[0.2-0.6] COPD/asthma. An EOS count ≥0.3 was seen in 33.5%, 55.6%, 49.6% and 64.4%, of individuals with no obstructive airways diseases, COPD, asthma, and COPD/asthma, respectively. Maximum Blood EOS level increase with age see figure 1. <fig><object-id>erj;64/suppl_68/PA440/F1</object-id><object-id>F1</object-id><object-id>F1</object-id><graphic></graphic></fig> <bold>Conclusions:</bold> Elevated blood EOS are found in more than half of individuals with obstructive airways diseases and surprisingly similar tendencies are seen in individuals with asthma and COPD. The usability of historical EOS in obstructive airways disease needs to be determined.