E-cigarettes for harm reduction among COPD patients who smoke: A pilot investigation.

OBJECTIVE: COPD patients who smoke struggle to quit and have higher rates of lung cancer relative to adults who smoke without COPD. E-cigarettes may be a potential harm reduction tool. This secondary analysis examined the impact of e-cigarette switching on smoking and associated health impacts among COPD patients who smoke. METHODS: COPD patients who smoke and were not motivated to quit (n = 46) completed a 12-week pilot e-cigarette switching trial. At week 12, participants were categorized by use category into complete/predominant switchers (past 7-day e-cigarette use and ≥50% reduction in cigarettes per day [CPD]) and non/partial switchers (exclusive cigarette smoking or past 7-day e-cigarette use with <50% reduction in CPD). Outcomes were examined by use category and included measures of exhaled carbon monoxide (eCO), respiratory and cardiovascular health, and aerobic capacity. Due to the pilot nature of the study, effect size estimates are presented. Multiple imputation was used for missing data. RESULTS: At week 12, 52.2% were classified as complete/predominant switchers and showed numerically greater reductions in eCO and improved COPD Assessment Test (CAT) scores (Hedge's g = 0.48 and 0.60, respectively; medium effects) relative to non/partial switchers. Improvements in arterial stiffness, aerobic fitness, lung functioning, and self-reported respiratory symptoms were more modest (Hedge's g range: 0.11-0.20; small effects). CONCLUSIONS: Half of COPD patients who smoke achieved at least a 50% reduction in smoking and improvements in COPD-related health outcomes. Results provide initial evidence for use of e-cigarettes for harm reduction among COPD patients who smoke.