Validation of Conventional Thromboembolic Risk Factors in a Korean Atrial Fibrillation Population　- Suggestion for a Novel Scoring System, CHA2DS2-VAK.

ABSTRACT

BACKGROUND: There is little evidence that focuses on the ethnic variability of clinical risk factors for thromboembolism (TE) in atrial fibrillation (AF). We aimed to investigate the effect of each traditional risk factor in the Korean AF population. Methods and Results: Medical records of 12,876 consecutive patients (aged >18 years) newly diagnosed and followed up with non-valvular AF from 2000 to 2013 were reviewed. TE events, including ischemic stroke and systemic embolism, were investigated for risk factor validation. Among the total of 12,876 patients, 1,390 (10.8%) had TE events. In univariate/multivariate analysis adjusting for clinical factors and antithrombotic medications, traditional risk factors included in the CHA2DS2-VASc scheme showed statistical significance, except for female sex, which was not a predictor of events. Additionally, chronic kidney disease (CKD; hazard ratio 1.62, P<0.001) was shown to be an independent predictor of TE events. Based on the analysis, we developed a novel stratification system, CHA2DS2-VAK, omitting the female sex category and adding CKD. The new scoring system showed greater discrimination in event rates between score 0 and 1 patients. CONCLUSIONS: Female sex was not associated with TE events in a Korean non-valvular AF population. The novel CHA2DS2-VAK scoring system, with substitution of CKD for female sex, might be more appropriate for the Korean population.