The Impact of Current Smoking on Severe Asthma in the Wessex Severe Asthma Cohort

<b>Background:</b> Current tobacco smoking impairs asthma control and accelerates decline in lung function, however the underlying pathobiological mechanisms for this are not well established. <b>Methods:</b> This abstract compares the clinical, physiological and biological characteristics of current and never smokers within the Wessex Severe Asthma Cohort (WSAC). This is a large published cohort including 342 well characterised severe asthma patients fulfilling the ATS/ERS 2014 definition of severe asthma. <b>Results:</b> The table below shows a comparison between current and never smokers from the WSAC. <b>Discussion:</b> Severe asthmatics who are current smokers have significantly poorer asthma control and quality of life. However, no statistically significant differences were identified in the clinical or physiological characteristics between the groups. No differences were seen in sputum inflammatory cell counts and whilst current smokers had lower peripheral blood eosinophil counts overall the proportion of patients with eosinophilic asthma was similar. Sputum IL-5 and ECP were lower in current smokers but sputum IL-8 was significantly higher suggesting a different pathobiological mechanism of eosinophilia.