Respiratory and Bronchitic Symptoms Predict Intention to Quit Smoking among Current Smokers with, and at Risk for, Chronic Obstructive Pulmonary Disease.

Abstract

Smoking cessation is the most important intervention for patients with chronic obstructive pulmonary disease (COPD). What leads smokers with COPD to quit smoking remains unknown. We sought to examine the association between respiratory symptoms and other markers of COPD severity with intention to quit smoking among a cohort of patients with probable COPD. We conducted a cross-sectional study of subjects with COPD or fixed airflow obstruction clinically diagnosed on the basis of pulmonary function testing. The subjects were identified in the COPD Outcomes-based Network for Clinical Effectiveness and Research Translation multicenter registry. The primary outcome was the intention to quit smoking within the next 30 days (yes or no), which was examined using model building with multivariable logistic regression, clustered by study site. We identified 338 current smokers with COPD via the registry. Of these subjects, 57.4% (n = 194) had confirmed airflow obstruction based on pulmonary function testing. Nearly one-third (29.2%; n = 99) intended to quit smoking in the next 30 days. In adjusted analyses, compared with subjects without airflow obstruction based on pulmonary function testing, subjects with Global Initiative for Chronic Obstructive Lung Disease stage I/II COPD were more likely to be motivated to quit (odds ratio [OR], 1.85; 95% confidence interval [CI], 1.37-2.49), with no association found for subjects with Global Initiative for Chronic Obstructive Lung Disease stage III/IV disease. Among the entire cohort, frequent phlegm (OR, 2.10; 95% CI, 1.22-3.64), cough (OR, 1.74; 95% CI, 1.01-2.99), wheeze (OR, 1.73; 95% CI, 1.09-3.18), and higher modified Medical Research Council dyspnea score (OR, 1.26 per point; 95% CI, 1.13-1.41) were associated with increased odds of intending to quit smoking. Low self-reported health was associated with decreased odds of intending to quit (OR, 0.75; 95% CI, 0.62-0.92). Frequent cough, phlegm, wheeze, and shortness of breath were associated with intention to quit smoking in the next 30 days, with a less clear relationship for severity of illness graded by pulmonary function testing and self-rated health. These findings can be used to inform the content of tobacco cessation interventions to provide a more tailored approach for patients with respiratory diseases such as COPD.