Men who stop smoking within 2 years of a chronic obstructive pulmonary disease (COPD) diagnosis have a lower risk for all-cause and cardiovascular mortality, according to study findings published in BMC Pulmonary Medicine.
Researchers in South Korea sought to evaluate the association between smoking cessation among men with COPD within 2 years of their diagnosis and the risk for all-cause and cause-specific mortality.
This retrospective cohort study used the Korean National Health Insurance Service (NHIS) database to identify 1740 male patients at least 40 years of age with COPD diagnosed between January 2003 and December 2014 who had smoked prior to diagnosis. Patients were stratified according to post-diagnosis smoking status as either “persistent smokers” or “quitters” (ie, those who quit within 2 years of their COPD diagnosis). Smoking status prior to and after diagnosis was determined using self-reported questionnaires.
All patients had been prescribed at least 1 COPD treatment medication at least twice per year. These included long-acting muscarinic antagonists (LAMA); long-acting beta-2 agonists (LABA); inhaled corticosteroids (ICS); short-acting muscarinic antagonists (SAMA) plus ICS and LABA; short-acting beta-2 agonist (SABA); methylxanthine; systemic corticosteroids; or systemic beta-2 agonists.
The results of our study suggest that quitting smoking after COPD diagnosis can lead to significant health benefits, and as such, support the current recommendation of smoking cessation.
Multiple covariates, including age, systolic blood pressure, alcohol consumption, and severity of COPD, were used in analysis to adjust for confounding.
Among all patients (mean age, 64.6 years; mean follow-up duration, 7.6 years), more than 30% stopped smoking after COPD diagnosis. Overall, 564 deaths occurred during follow-up. Among those who quit, the risk for all-cause mortality was reduced by 17% (adjusted hazard ratio [aHR], 0.83; 95% CI, 0.69-1.00) and the risk for cardiovascular mortality was reduced by almost 45% (aHR, 0.56; 95% CI, 0.33-0.95) compared with those who smoked persistently.
Patients who stopped smoking vs those who smoked persistently were more likely to be older, have higher systolic blood pressure, drink alcohol less frequently, have severe COPD, and have a higher prevalence of cancer.
In stratified analysis evaluating subgroups, the investigators found no significant interaction between the effect of quitting smoking and the risk for all-cause mortality for individual risk factors of age, alcohol consumption, severity of COPD, presence of hypertension, cancer, or cardiovascular disease.
Study limitations include the use of self-reported questionnaires, which may not be totally reliable, and the exclusion of women from the study.
“Quitting smoking within 2 years after COPD diagnosis was associated with lower risk of all-cause and cardiovascular mortality relative to persistent smokers,” investigators concluded. “The results of our study suggest that quitting smoking after COPD diagnosis can lead to significant health benefits, and as such, support the current recommendation of smoking cessation.”