LAUSR

Background Patients presenting with an acute exacerbation of COPD (AECOPD) and a peripheral blood eosinophil count≥=2% of the total white cell count have a better response to oral cortico-steroids, suggesting that stratification by this biomarker identifies a pathologically distinct phenotype and has clinical value.1 We have tested the hypothesis that the eosinophilic and non-eosinophilic exacerbations of COPD have different seasonality using a dataset of patents admitted to an inner London teaching hospital with AECOPD over 9 years. Methods All admissions with AECOPD were recorded between 2004 and 2012. We recorded the first blood test result within 24 hours of admission. The month of admission was recorded. Seasons were defined as per figure 1 and the distribution of eosinophilic (blood eosinophil count≥=2%) and non-eosinophilic events compared. Abstract P187 Figure 1 Results 2793 admissions with AECOPD were recorded, of which 2416 (86.5%) had a FBC result available and 750 (31.0%) were eosinophilic. The mean age of the entire population was 70 with 44.3% female. Eosinophilic admissions had a median age 69.3 of which 40.5% were female. Non-eosinophilic admissions had a median age 70.9 of which 46.9% were female. There were no significant differences between the number of eosinophilic exacerbations across seasons. In contrast, non-eosinophilic exacerbations occurred more commonly in winter compared to summer. The proportion of eosinophilic events was 36.5 vs 28.1% in summer and winter respectively (mean difference 9%; 95% CI 4%–14%; p=0.003). Figure 1 – Admissions via A and E for patients with Acute Exacerbations of COPD between 2004 and 2012 stratified by season and peripheral blood eosinophil percentage. Discussion Exacerbations of COPD associated with a higher blood eosinophil count do not vary according to season whereas non-eosinophilic exacerbations occur more commonly in winter and account for a significantly higher proportion of winter events. Reference Bafadhel M, McKenna S, Terry S, et al. Blood eosinophils to direct corticosteroid treatment of exacerbations of chronic obstructive pulmonary disease: A randomised placebo-controlled trial. Am J Respir Crit Care Med2012;186(1):48–55. doi:10.1164/rccm.201108-1553OC