"Smoker's Paradox" in Patients Treated for Severe Injuries: Lower Risk of Mortality After Trauma Observed in Current Smokers

Abstract

Background: Studies evaluating the effect of smoking status on mortality outcomes in trauma patients have been limited, despite the fact that survival benefits of smoking have been reported in other critical care settings. The phenomenon "smoker's paradox" refers to the observation that following acute cardiovascular events, such as acute myocardial infarction and cardiac arrest, smokers often experience decreased mortality in the hospital setting. The objective of our study was to determine whether smoking imparts a survival benefit in patients with traumatic injuries.

Methods: We performed a retrospective cohort study that analyzed cases included in the National Trauma Data Bank research dataset. Hierarchical logistic regression analyses were used to determine whether smoking alters the risk of mortality and complications in patients who smoke.

Results: The percentage of patients experiencing mortality differed significantly between smokers (n = 38,564) and nonsmokers (n = 319,249) (1.8% vs. 4.3%, P < .001); however, the percentage experiencing a major complication did not (9.7% vs. 9.6%, P = .763). Regression analyses indicated that smokers were significantly less likely to die during the hospital stay compared to nonsmokers after adjusting for individual and hospital factors (OR = 0.15; CI = 0.10, 0.22). Additionally, smokers were also less likely to develop a major complication than nonsmokers (OR = 0.73, CI = 0.59-0.91).

Conclusions: Patients who smoke appear to have a much lower risk of in-hospital mortality than nonsmokers. Further investigation into biological mechanisms responsible for this effect should be carried out in order to potentially develop therapeutic applications.