Background: Active smoking is associated with elevated thrombotic risk. Smoking status has recently been incorporated into the SAMe-TT2R2 (sex female, age < 60 years, medical history [more than two comorbidities], treatment [interacting drugs, eg, amiodarone for rhythm control], tobacco use [doubled], race [doubled]) score that can help predict poor international normalized ratio control in patients with atrial fibrillation (AF) treated with vitamin K antagonists (VKAs). The clinical benefit of antiplatelet therapy (APT) has been seen primarily in smokers. We hypothesized that active smoking may differently influence the risks of stroke and bleeding in patients with AF treated with VKAs or with APT.
Methods: We examined the clinical course of 7,809 consecutive patients with AF seen between 2000 and 2010. Outcomes in patients who were active smokers were compared with those in other patients.
Results: Among 7,809 patients with AF, 1,034 (13%) were active smokers. APT was prescribed on an individual basis for 2,761 patients (35%) and VKAs for 4,534 (57%). After a follow-up of 929 ± 1,082 days (median = 463 days, interquartile range = 1,564 days), smoking was not independently associated with a higher risk of stroke/thromboembolic event in patients with AF (hazard ratio [HR], 0.95; 95% CI, 0.78-1.22; P = .66). On multivariate analysis, smoking was independently associated with a worse prognosis for the risk of severe bleeding (HR, 1.23; 95% CI, 1.01-1.49; P = .04) and for the risk of major Bleeding Academic Research Consortium bleeding (HR, 1.40; 95% CI, 1.02-1.90; P = .03). Smoking was independently associated with a higher risk of bleeding in patients treated with VKAs (HR, 1.32; 95% CI, 1.04-1.67; P = .02), whereas the risk was nonsignificant in patients treated with APT (HR, 1.28; 95% CI, 0.94-1.74; P = .11).
Conclusions: In AF, there was a higher risk of severe bleeding in smokers, mainly in those treated with VKAs.