Outcomes and predictive factors for successful smoking cessation therapy in COPD patients with nicotine dependence

Background: The data on smoking cessation treatment outcomes for smokers with chronic obstructive pulmonary disease (COPD) are limited. The present study assessed the effectiveness of smoking cessation interventions at our clinic. Methods: Data from a prospective registry of a 3-month smoking cessation program were evaluated. The primary outcome, smoking cessation, was defined as the complete abstinence from smoking between the 8-week and 12-week clinic visits. Pulmonary function and health-related quality of life using St. George's Respiratory Questionnaire (SGRQ) were assessed at baseline and at the end of the program. Results: Out of the 155 COPD patients with nicotine dependence (female/male = 39/116; mean age, 67.2 +/- 9.8 years; mean forced expiratory volume in 1 s (FEV1), 59.7 +/- 21.1% predicted), 107 participants completed the program. Among the completers, 74 achieved smoking cessation. In the multivariate analysis, mental disorders (odds ratio [OR] 3.678, 95% confidence interval [CI]: 1.182, 11.445), higher exhaled carbon monoxide (CO) level (OR 1.080, 95% CI: 1.013, 1.151) and lower FEV1/forced vital capacity (FVC) (OR 0.958, 95% CI: 0.923, 0.995) were negatively associated with successful smoking termination. Significant changes in pulmonary function were found in quitters but not in continuous smokers (increases in FEV1 by 0.09 L/s [95% CI: 0.03, 0.15] and peak expiratory flow by 0.23 L/s [95% CI: 0.01, 0.44]). SGRQ total scores improved significantly in both quitters (-5.4 [95% CI: -8.4, -2.5]) and continuous smokers (-7.0 [95% CI: -11.6, -2.5]). Conclusion: In the program completers, the exhaled CO levels, FEV1/FVC ratio, and presence of mental disorders were significantly associated with program success or failure in COPD patients with nicotine dependence. (c) 2020 The Japanese Respiratory Society. Published by Elsevier B.V. All rights reserved.