Author(s): Shaker SB, Stavngaard T, Laursen LC, Stoel BC, Dirksen A
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Abstract INTRODUCTION: Whether smoking-induced lung inflammation subsides after smoking cessation is currently a matter of debate. We used computed tomography (CT) to evaluate the effect of smoking cessation on lung density in patients with COPD. MATERIAL AND METHODS: Thirty-six patients quit smoking out of 254 current smokers with COPD who were followed with annual CT and lung function tests (LFT) for 2?4 years as part of a randomised placebo-controlled trial of the effect of inhaled budesonide on CT-lung density. Lung density was expressed as the 15th percentile density (PD15) and relative area of emphysema below -910 HU (RA-910). From the time-trends in the budesonide and placebo groups the expected CT-lung densities at the first visit after smoking cessation were calculated by linear regression and compared to the observed densities. RESULTS: Following smoking cessation RA-910 increased by 2.6\% (p = 0.003) and PD15 decreased by -4.9 HU (p = 0.0002). Furthermore, changes were larger in the budesonide group than the placebo group (PD15: -7.1 vs -2.8 HU. RA-910 3.7\% vs 1.7\%). These differences were, however, not statistically significant. The LFT parameters (FEV(1) and diffusion capacity) were not significantly influenced by smoking cessation. CONCLUSION: Inflammation partly masks the presence of emphysema on CT and smoking cessation results in a paradoxical fall in lung density, which resembles rapid progression of emphysema. This fall in density is probably due to an anti-inflammatory effect of smoking cessation.
This article was published in COPD
and referenced in Journal of Pulmonary & Respiratory Medicine