Risk factors for frequent exacerbations in (ex)smoking and never-smoking adult-onset asthma patients

Abstract

Rationale: Smoking influences airway inflammation, asthma severity and response to therapy in asthma patients. Consequently, risk factors for exacerbations may differ between (ex)smokers and never-smokers. Aim: To identify risk factors for frequent exacerbations in (ex)smoking and never-smoking asthmatics. Methods: Clinical, functional and inflammatory parameters from a cohort of 571 adult-onset asthma patients were used. Patients with uncontrolled asthma despite high dose asthma medication (GINA step 4-5) were selected (n=165). Logistic regression analysis was used to identify risk factors for frequent exacerbations (≥3 oral corticosteroid (OCS) bursts in the previous year) in (ex)smoking (n=92) and never-smoking (n=73) patients. Results: (Ex)smokers with frequent exacerbations (n=38) had a longer duration of asthma, used higher doses of inhaled corticosteroids (ICS), used more often OCS, had lower FEV 1 and higher blood neutrophils than patients with 1 , had increased airway hyperresponsiveness and had higher blood eosinophils than patients with Conclusion: Higher ICS dose and blood neutrophils are risk factors for frequent exacerbations in (ex)smokers, whereas higher blood eosinophils are risk factors in never-smokers. This suggests that exacerbations in smoking and never-smoking asthmatics have different aetiologies.