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

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.

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.

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.