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Reduced airway lumen area, poor symptom control linked in smokers with asthma

The segmental airway lumen area was reduced in smokers with asthma compared with nonsmokers with asthma and was associated with poor symptom control and small airway dysfunction, according to study results.

Neil C. Thomson, MD, of the Institute of Infection, Immunity and Inflammation at the University of Glasgow, and colleagues conducted a cross-sectional study on 93 participants with asthma, including 46 smokers, to determine if symptom control in smokers was linked with narrowed segmental airways and, or, increased wall thickness. Measurements were made via computed tomography.

Median RB10 (smaller airway) measurements indicated a decrease in airway lumen area in the smoking cohort (16.6 mm²) vs. nonsmokers (19.6 mm²; P = .01), particularly among smokers with severe asthma. LB10 measurements showed similar results with smokers who had asthma having smaller airway lumen areas (14.8 mm² vs. 19.9 mm²; P = .003) than never smokers. Wall thicknesses were not significantly different for RB10 and LB10 between smokers and nonsmokers.

The reduced airway lumen in the smaller airways RB10 (ACQ-6 score = –0.463; P = .001) and LB10 (ACQ-6 score = –0.401; P = .007) of smokers with asthma was associated with poor symptom control. There was no association between poor symptom control in the never smokers. This lack of control also was linked with a diminished postbronchodilator FEV¹/FVC (–0.328, P = .014) in smokers with asthma.

“In the current study, smokers with asthma had higher ACQ-6 scores indicating poor current symptom control,” the researchers wrote. “These findings suggest that a reduced segmental airway lumen area, along with other factors including corticosteroid insensitivity, may contribute to worse current symptom control in smokers with asthma compared with never smokers with asthma.”

Disclosure: Thomson reports no relevant financial disclosures. Please see the full study for a list of all other authors’ relevant financial disclosures.