CHA2DS2-VASc score for ischaemic stroke risk stratification in patients with chronic obstructive pulmonary disease with and without atrial fibrillation: a nationwide cohort study.

Aims: We conducted this nationwide cohort study to identify the performance of CHA2DS2-VASc score for ischaemic stroke risk stratification in chronic obstructive pulmonary disease (COPD) patients whether they had comorbid atrial fibrillation (AF) or not. Methods and results: Using the longitudinal health insurance database 2000, patients aged ≥20 years with newly diagnosed COPD from 2000 to 2011 with at least three claims for outpatient and/or hospitalization visits were identified. A total of 1492 COPD patients with AF and 50 343 COPD patients without AF were included in this study. We calculated the CHA2DS2-VASc score-specific incidence density rates of ischaemic stroke with person-years in each cohort. Cox models were conducted to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) of ischaemic stroke risk in COPD patients with and without concomitant AF. The predictive performance of CHA2DS2-VASc score with regard to ischaemic stroke events was assessed using area under the receiver operating characteristic curve (C-statistic). COPD patients with a higher CHA2DS2-VASc score were more likely to develop ischaemic stroke whether or not AF was present. Moreover, the C-statistics of CHA2DS2-VASc score in predicting ischaemic stroke in COPD patients with and without AF were 0.58 (95% CI = 0.55-0.62) and 0.71(95% CI = 0.70-0.72), respectively. Conclusions: Our study is the first to show that the performance of CHA2DS2-VASc score in predicting ischaemic stroke is better for COPD patients without AF than for COPD patients with AF.