Objective

To determine the impact of smoking status in the prediction of stroke using CHADS₂ and CHA₂DS₂-VASc schemes.

Methods

Five hundred twenty-eight consecutive patients with arrhythmic symptoms and without any documented arrhythmia from Queen Mary Hospital, Hong Kong, were followed up to determine the incidence of ischemic stroke, new-onset atrial fibrillation (AF), or all-cause mortality. Smoking status was classified into nonsmokers and smokers. The pairwise comparisons of C-statistics for outcomes were performed.

Results

During a median follow-up period of 6.2 years, 65 (12.3%) individuals developed ischemic stroke. Smokers experienced higher annual incidence of stroke, a new-onset AF, and all-cause death compare to nonsmokers, with corresponding hazard ratio (HR) of stroke, AF, and all-cause death being 2.51 (95% confidence intervals, CI 1.36als, CIse death bein 1.15a3.24), and 1.95 (95% CI 1.161.95 (95% CIath being 2.51 (95% confidence corr₂ and CHA₂DS₂-VASc for stroke were 0.60 (95% CI 0.51 for stp = 0.09) and 0.59 (95% CI 0.50 (95%, p = 0.15) respectively, whereas the C-statistics of CHADS₂ and CHA₂DS₂-VASc were 0.66 (95% CI 0.61 were 0p = 0.005), 0.75 (95% CI 0.7 CI 0.7p < 0.0001), respectively among nonsmokers. After incorporating smoking, both the CHADS₂-smoking and CHA₂DS₂-VASc-smoking achieved better C-statistics for new-onset ischemic stroke prediction superior to baseline score systems in male groups.

Conclusion

Cigarette smoking status has impact on stroke stratification using CHADS₂ and CHA₂DS₂-VASc scheme. The discrimination of the CHADS₂ and CHA₂DS₂-VASc scheme for stroke can be significantly improved if smoking status is additionally considered.