Cigarette smoke retention and bronchodilation in patients with COPD. A controlled randomized trial

Abstract

Introduction: Bronchodilators are the cornerstone for symptomatic treatment of chronic obstructive pulmonary disease (COPD). Many patients use these agents while persisting in their habit of cigarette smoking. We hypothesized that bronchodilators increase pulmonary retention of cigarette smoke and hence the risk of smoking-related (cardiovascular) disease. Our aim was to investigate if bronchodilation causes increased pulmonary retention of cigarette smoke in patients with COPD. Methods: A double-blinded, placebo-controlled, randomized crossover trial, in which COPD patients smoked cigarettes during undilated conditions at one session and maximal bronchodilated conditions at the other session. Co-primary outcomes were pulmonary tar and nicotine retention. We performed a secondary analysis that excludes errors due to possible contamination. Secondary outcomes included the biomarkers C-reactive protein and fibrinogen, and smoke inhalation patterns. Results: Of 39 randomized patients, 35 patients completed the experiment and were included in the final analysis. Bronchodilation did not significantly increase tar retention (-4.5%, p = 0.20) or nicotine retention (-2.6%, p = 0.11). Secondary analysis revealed a potential reduction of retention due to bronchodilation: tar retention (-3.8%, p = 0.13), and nicotine retention (-3.4%, p = 0.01). Bronchodilation did not modify our secondary outcomes. Conclusions: Our results do not support the hypothesis that cigarette tar and nicotine retention in COPD patients is increased by bronchodilation, whereas we observed a possibility towards less retention. Trial registration: www.clinicaltrials.gov: NCT00981851.