Clinical Characteristics of Smoking Asthmatics

Abstract

Background: The smoking prevalence in asthma patients are similar to those in the general population. Asthma and active cigarette smoking can interact to create more severe symptoms, an accelerated decline in lung function and impaired therapeutic responses. Accordingly, asthmatics with a history of smoking were examined to define the clinical characteristics and lung function of smoking asthmatics. Methods: The medical records of 142 asthmatics with a known smoking history were reviewed. The patients were divided into three groups according to their smoking history - current smokers, former smokers and non-smokers. The clinical characteristics, lung function, and annual declines of the forced expiratory volume in one second (FEV 1) were compared. Results: Fifty-three of the 142 patients (37%) were current smokers, 24 were former smokers (17%) and 65 were non-smokers (45%). The patients with a hospital admission history during the previous year included 16 current smokers (30%), 4 former smokers (17%) and 7 non-smokers (11%) (p=0.02). The mean FEV 1 (% predicted) was 76.8±19.8%, 71.6±21.1% and 87.9±18.7% for current smokers, former smokers and non-smokers, respectively (p＜ 0.001). The FEV1/forced vital capacity (FVC) (ratio, %) values were 63.6±12.6%, 59.3±14.9% and 72.1±11.8% in current smokers, former smokers and non-smokers, respectively (p＜0.001). The corresponding mean values for the individual FEV1 slopes were not significant (p=0.33). Conclusion: Asthmatic smokers demonstrated higher hospital admission rates and lower lung function. These findings suggest that the smoking history is an important predictor of a poor clinical outcome in asthma patients.