Study objectives: To investigate the relationship between direct or environmental tobacco smoke (ETS) exposure and both hospital-based care (HBC) and quality of life (QOL) among subjects with asthma.
Study design: We report baseline cross-sectional data on 619 subjects with asthma, including direct or ETS exposure and QOL, and prospective longitudinal data on HBC using administrative databases for 30 months following baseline evaluation.
Setting and patients: Participants were health maintenance organization members with physician-diagnosed asthma involved in a longitudinal study of risk factors for hospital-based asthma care.
Measurements: Demographic characteristics and QOL were assessed with administered questionnaires, including the Marks Asthma Quality-of-Life (AQLQ) and SF-36 questionnaires. HBC was defined as episodes per person-year of hospital-based asthma care, which included emergency department and urgency care visits, and hospitalizations for asthma.
Results: Current smokers reported significantly worse QOL than never-smokers in two of five domains of the AQLQ (p < 0.05). Subjects with ETS exposure also reported significantly worse QOL than those without ETS exposure in two domains (p < 0.05). On the SF-36, current smokers reported significantly worse QOL than never-smokers in five of nine domains (p < 0.05). Subjects with ETS exposure reported significantly worse QOL than those without ETS exposure in three domains (p < 0.05). Current smokers used significantly more hospital-based asthma care than never-smokers (adjusted relative risk [RR], 1.40; 95% confidence interval [CI], 1.01 to 1.95) while ex-smokers did not exhibit increased risk compared with nonsmokers (adjusted RR, 0.94; 95% CI, 0.7 to 1.3). Also, subjects with ETS exposure used significantly more hospital-based asthma care than those without ETS exposure (RR, 2.34; 95% CI, 1.80 to 3.05).
Conclusions: Direct or environmental tobacco exposure prospectively predicted increased health-care utilization for asthma and reduced QOL in patients with asthma. These findings add to our existing knowledge of the detrimental effects of tobacco smoke and are of relevance specifically to patients with asthma.