Possible involvement of smoking in the development of asthma-like conditions in patients with chronic obstructive pulmonary disease

Abstract

Indicies of asthma were measured in smokers with chronic bronchitis (CB) + pulmonary emphysema (PE), smokers with CB only, and non-smokers with CB, to examine whether smoking is involved in the development of asthma-like condition in patients with chronic obstructive pulmonary disease (COPD). Airway hypersensitivity was measured with an Astrograph method, and the reversibility of airway obstruction was measured as improvement in FEV1.0 and as percent change in FEV1.0 after inhalation of a beta-agonist. Both hypersensitivity and reversibility were significantly higher in smokers with CB+PE and in smokers with CB only than in non-smokers with CB. The number of eosinophils in sputum, but not in peripheral blood, was slightly higher in the smokers than in the non-smokers. The serum levels of IgE were significantly higher in the smokers than in the non-smokers. No significant difference in the rate of positive skin tests for common allergens was observed among the three groups, but the rate of positive tests for Broncasma Berna was very high in the smokers, and all such tests were negative in the non-smokers. These results indicate that among patients with COPD an asthmatic component is more frequently found in smokers than in non-smokers, and suggest that smoking plays some part in the development of asthma-like condition in these diseases.