Abstract
BACKGROUND: Cigarette smoking aggravates asthma exacerbations, yet some patients with asthma continue to smoke. AIMS: To compare the quality of life of adult smokers and non-smokers with asthma. METHODS: Asthma Quality of Life (AQLQ) questionnaires were administered to adult patients with asthma managed in primary care in Singapore. The survey also included data of their asthma status including symptom profiles. Independent two-sample t-test, ANCOVA model, χ2 test and ordinal logistic regression were used to compare the mean domain scores and the effect of smoking on nocturnal symptoms and awakening, respectively. RESULTS: 357 adult asthma patients (183 non-smokers and 174 smokers) were recruited. Smokers were mainly male (p<0.001), single (p=0.008), and younger (mean age 30 years) (p=0.007). They were more affected by nocturnal cough and wheezing (p=0.016). After adjustment for age, gender, and asthma medications, the mean scores of the AQLQ 'symptoms' and 'emotional function' domains of smokers were 0.41 (95% CI 0.10 to 0.72) and 0.50 (95% CI 0.16 to 0.84) points lower than for non-smokers, with no statistical differences in the 'activity limitations' and 'exposure to environmental stimuli' domains. CONCLUSIONS: Adult patients with asthma who smoke are more affected by nocturnal symptoms, with lower 'emotional function' scores in the AQLQ.