John A. Cairns, MD
In patients with atrial fibrillation (AF) who were not prescribed vitamin K antagonists or heparins, how well do 2 risk stratification scales predict risk for thromboembolism?
Registry-based cohort study for validation of 2 existing risk prediction scales.
73 538 patients (60% ≥ 75 y, 51% women) who had a discharge diagnosis of nonvalvular AF or atrial flutter and did not have previous mitral or aortic valve disease or surgery. Exclusion criteria were death or thromboembolism ≤ 7 days after discharge or use of vitamin K antagonists or heparins ≤ 180 days before discharge or ≤ 7 days after discharge.
CHADS2 scale (score range 0 to 6): Congestive heart failure, Hypertension, Age ≥ 75 years, and Diabetes mellitus (1 point each); and previous thromboembolism (peripheral artery embolism, ischemic Stroke, or pulmonary embolism) (2 points). CHA2DS2-VASc scale (score range 0 to 9): same 5 items and scores as CHADS2 but with 2 points for age ≥ 75 years and addition of Vascular disease (1 point), Age 65 to 74 years (1 point), and female Sex (1 point). For both scales, low risk for thromboembolism = score 0; intermediate risk = score 1; and high risk = score ≥ 2.
Hospitalization for or death due to thromboembolism.
More patients were classified as low risk (22% vs 8.7%) or intermediate risk (32% vs 11%) for thromboembolism using CHADS2 than CHA2DS2-VASc. Discrimination of risk for thromboembolism by risk category was better with CHA2DS2-VASc than CHADS2 (Table); discrimination by risk score (0 to 9 and 0 to 6, respectively) was similar for both scales.
CHA2DS2-VASc had better discrimination than CHADS2 for predicting risk for thromboembolism in patients with atrial fibrillation.
Thromboembolism predicted by 2 risk stratification scales in patients with atrial fibrillation*
*Abbreviations defined in Glossary.
†CHADS2 = Congestive heart failure, Hypertension, Age ≥ 75 y, Diabetes mellitus, and previous thromboembolism (double points); CHA2DS2-VASc = Congestive heart failure, Hypertension, Age ≥ 75 y (double points), Diabetes mellitus, previous thromboembolism (double points), Vascular disease, Age 65 to 74 y, and female Sex.
‡Based on Cox regression models using 3 risk groups and with covariates analyzed as categorical variables.
Cairns JA. CHA2DS2-VASc had better discrimination than CHADS2 for predicting risk for thromboembolism in atrial fibrillation. Ann Intern Med. ;154:JC5–13. doi: 10.7326/0003-4819-154-10-201105170-02013
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Published: Ann Intern Med. 2011;154(10):JC5-13.
Cardiology, Rhythm Disorders and Devices.
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