Asthma control is associated with smoking status: Findings from WATCH

Background: Difficult asthmatics with a history of smoking, experience increased lung reactivity. Associations between related comorbidities need further investigation. Aim: To evaluate the symptoms of difficult asthmatics in relation to smoking status, in the Wessex AsThma Cohort of difficult asthma (WATCH) Southampton, UK. Methods: The smoking status of 377 adult asthmatics in WATCH was assessed for asthma control, symptoms of hyperventilation and depression. A retrospective analysis compared smoking status of difficult asthmatics using Chi square (categorical data) and Kruskall-Wallis (continuous data). Results: 180 (48%) had a history of smoking, of whom 13 continued to smoke. Differences in smoking status were not associated with BMI, but did differ by sex, age and age at diagnosis. Asthma control and symptoms of hyperventilation in ex-smokers was comparable to that of never smokers. Current smoking was associated with increased symptoms of depression and decreased attentional control than ever smokers. Conclusion: Prevalence of smoking in difficult asthma is low, but is associated with lack of asthma and attentional control, hyperventilation and depression. These findings highlight the benefits of smoking cessation.