Revisiting the Smoking Paradox in Acute Ischemic Stroke Patients: Findings From the Chinese Stroke Center Alliance Study

Abstract

Background Smoking is a well‐established risk factor for the development of acute ischemic stroke (AIS). However, the “smoker's paradox” suggests that it is associated with favorable clinical outcomes following stroke. We aimed to reevaluate the association between smoking and in‐hospital outcomes in patients with AIS in contemporary practice. Methods and Results A total of 649 610 inpatients with AIS from 1476 participating hospitals in the Chinese Stroke Center Alliance were included. In‐hospital outcomes measurement included all‐cause mortality, discharge against medical advice, and complications. Multivariable logistic regression models adjusting for baseline characteristics, clinical profiles at presentation, and in‐hospital management were used to evaluate the association between smoking and in‐hospital outcomes. A propensity score–matched analysis was also conducted. Of these patients with AIS, 36.8% (n=238 912) were smokers. Smokers were younger, had fewer comorbidities, and had slightly lower rates of adverse in‐hospital outcomes than nonsmokers (all‐cause death or discharge against medical advice: 6.0% versus 6.1%; in‐hospital complications: 14.5% versus 15.1%). Multivariable analysis revealed that smoking was associated with higher risk of adverse in‐hospital outcomes (all‐cause death or discharge against medical advice: odds ratio [OR], 1.05 [95% CI, 1.02–1.08]; P <0.001; complications: OR, 1.06 [95% CI, 1.04–1.08]; P <0.001). The excess risk of adverse in‐hospital outcomes remained in smoking patients with AIS after propensity score‐matching analysis (all‐cause death or discharge against medical advice: OR, 1.04 [95% CI, 1.00–1.08]; P =0.034; complications: OR, 1.05 [95% CI, 1.03–1.08]; P <0.001). Conclusions Smoking was associated with increased risk of adverse in‐hospital outcomes among patients with AIS in contemporary practice, reinforcing the importance of smoking cessation in patients with AIS.