Eosinophilic phenotypes of overlapping respiratory diseases in an Italian general population sample

Aim: to quantify the distribution of overlapping diagnosis of Asthma (A), Chronic Bronchitis (CB) and Emphysema (E), stratifying by blood eosinophilia (EOS+/EOS-). To evaluate the role of environmental/host risk factors for eosinophilic phenotypes of A and COPD (CB+E). Methods: 1919 subjects (8-88 yrs, 49% males) enrolled in an Italian cross-sectional study (1991-93), filled in a questionnaire on respiratory symptoms/diseases and risk factors and underwent a blood test. Eosinophil count is expressed as % of total leucocytes (EOS+ >3%). A double proportional Venn diagram is used to show the distribution of A, CB, E and their overlapping categories. A Multinomial Logistic Regression were run to assess the association of A or COPD eosinophilic phenotypes with gender, age, smoke, work exposure, eczema, rhinitis and diagnosis of asthma or COPD (Odd Ratio-OR, Confidence Interval-CI 95%). AsmaEOS+ and AsmaEOS- are associated with COPD (OR 5.1 vs 6.9) and rhinitis (6.3 vs 2.4); AsmaEOS+ is also associated with age<25 (3.1) and smoke (0.4).As for COPD, we pinpoint the association of COPDEOS+ and COPDEOS- with work exposure (3.3 vs 1.6) and the association of COPDEOS- with rhinitis (0.4). Conclusions: eosinophilic pattern is more frequent in young people and generally EOS+ subjects tend to be non smokers. The results confirm the expected overlap among respiratory diagnosis and show higher values in EOS- condition.