Relationship between smoking and adverse outcomes in patients with atrial fibrillation: A meta-analysis and systematic review

Abstract Background Several studies have investigated the impact of smoking on the prognosis of atrial fibrillation (AF), but the results remain controversial. We therefore aimed to estimate the association between smoking and adverse outcomes in patients with AF. Methods We systematically searched the Cochrane Library, PubMed, and Elsevier databases through May 2016 for studies regarding the association between smoking and adverse outcomes in AF patients. Risk ratios [RRs] and 95% confidence intervals [CIs] were abstracted and then pooled using a random-effects model. Results A total of 8 cohort studies with 87,373 participants were included in this meta-analysis. Among patients with AF, smoking was associated with increased risks of all-cause death (RR = 1.82, 95% CI: 1.33–2.49, P = 0.0002) and cardiovascular death (RR = 1.54, 95% CI: 1.31–1.81, P < 0.00001) but not stroke/thromboembolism (RR = 1.19, 95% CI 0.97–1.46; P = 0.10). In addition, smoking was associated with an increased risk of major bleeding (RR = 1.93, 95% CI 1.08–3.47, P = 0.03), even after adjustment for the antithrombotic treatment. Conclusions The published literature demonstrates that smoking is not associated with the risk of stroke/thromboembolism but increases the risks of all-cause death and cardiovascular death in AF patients, as well as the risk of major bleeding in AF patients using anticoagulants.