Twelve Weeks of Successful Smoking Cessation Therapy with Varenicline Reduces Spirometric Lung Age

Objective We evaluated the short-term effects of smoking cessation therapy with varenicline on the lung function. Methods In this study, 81 subjects received 12 weeks of smoking cessation therapy with varenicline. No changes were made to any previously prescribed medications. A physical examination, blood sampling, and spirometry were performed at the first and last visit. Spirometric lung ages were calculated by a formula based on height and the forced expiratory volume in 1 second. The success group comprised 62 subjects who attained 4-week continuous abstinence confirmed by exhaled carbon monoxide testing; whereas the failure group comprised 19 subjects who did not attain this result. However, the number of cigarettes consumed per day was reduced in all subjects of the failure group. Results The spirometric lung ages significantly improved over the 12-week period in the success group (69.8±24.7 vs. 66.9±24.1, p<0.01); however, spirometric lung ages significantly deteriorated in the failure group (70.5±25.5 vs. 73.7±26.9, p<0.01). The effect sizes (Cohen's d) of spirometric lung age in the success and failure groups were 0.37 and 0.81, respectively. The post-hoc statistical power of the spirometric lung age in the success and failure groups was 0.83 and 0.91, respectively. According to a multiple regression analysis, success in smoking cessation exhibited an independent association with the difference in spirometric lung age between the last visit and baseline (p<0.01). Conclusion These findings suggest that successful smoking cessation therapy with varenicline improves the spirometric lung age in the short term.