CHA2DS2-VASc risk score for stroke risk:
Calculates stroke risk for patients with atrial fibrillation.
Research authors: Lip GY, Nieuwlaat R, Pisters R, Lane DA, Crijns HJ.
Details Formula Study characteristics Files & References
Model author
Model ID
Revision date
MeSH terms
  • Atrial Fibrillation
  • Clinical Prediction Rule
  • Stroke
  • Model type
    Linear model (Calculation)
    No Formula defined yet
    Condition Formula

    Additional information

    CHA2DS2-VASc score (Birmingham 2009) was developed after identifying additional stroke risk factors in patients with atrial fibrillation.
    Validation study included 1,084 patients with non-valvular AF, not on anticoagulation, over age 18 with EKG or Holter diagnosed AF in the ambulatory and hospital settings from 182 hospitals in 35 countries from 2003 to 2004 and had known thromboembolic status at 1 year from the Euro Heart Survey database.
    End point used was stroke or other thromboembolic event.
    Used previously developed Birmingham 2009 schema, under the acronym CHA2DS2-VASc.
    Study showed that as CHA2DS2-VASc score increased, rate of thromboembolic event within 1 year in non-anticoagulated patients with non-valvular AF increased as well.
    Considered score of 0 to be low risk for TE events (none seen in cohort at one year), score of 1 intermediate risk (0.6% rate at 1 year), and greater than 1 high risk (3% rate at 1 year).
    oints to keep in mind:
    31% of the patients in their original study group were lost to follow-up at one year and thus were not included in the analysis. These patients could have had thromboembolic events, causing them to be lost to follow-up.
    There was no statistically significant difference found between the CHA2DS2-VASc and CHADS2 risk stratification schema in predicting TE events.
    None of the included patients were anticoagulated. Those at particularly high risk for a TE event may have been already anticoagulated by their PMD, potentially skewing the TE rates.
    A subsequent study examining the performance of CHA2DS2-VASc in predicting TE events on anticoagulated patients also identified CAD and smoking as potential additional risk factors for TE in this subset of patients. However, that study also did not show a statistical difference in the predictive avarious risk stratification abilities of the scores.

    Study Population

    Total population size: 1084
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    Females: {{ model.numberOfFemales }}

    Continuous characteristics

    Name Mean SD Unit
    Age 66 14 years
    Systolic blood pressure 139 23 mmHg
    Left ventricular ejection fraction 53 14 %
    Name LL Q1 Median Q3 UL Unit
    te 12 23 66 134 222 t

    Categorical characteristics

    Name Subset / Group Nr. of patients
    Age ≥75 309
    <75 775
    Past medical history: stroke Yes 45
    No 1039
    Past medical history: transient ischemic attack Yes 46
    No 1038
    Past medical history: other systemic embolism Yes 6
    No 1078
    Past medical history: coronary artery disease Yes 412
    No 672
    Past medical history: peripheral vascular disease Yes 62
    No 1022
    Past medical history: hypertension Yes 729
    No 355
    Past medical history: diabetes mellitus Yes 187
    No 897
    Past medical history: heart failure Yes 253
    No 831
    Drugs: ACE inhibitor/angiotensin II receptor blocker Yes 607
    No 477
    Drugs: Statins Yes 252
    No 834
    Drugs: antiplatetelet drugs Yes 802
    No 282
    CHA2DS2-VASc risk score for stroke risk:
    Refer to Intended Use for instructions before use
    Evidencio B.V., Irenesingel 19, 7481 GJ, Haaksbergen, the Netherlands

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    Calculated CHA2DS2-VASc risk score: points

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    Outcome stratification

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    Conditional information

    Result interpretation

    This model calculates stroke risk for patients with atrial fibrillation. The CHA2DS2-VASc risk score (acronym: Birmingham 2009) fared marginally better (C-statistic, 0.606) than CHADS(2). However, those classified as low risk by the CHA2DS2-VASc and NICE schema were truly low risk with no TE events recorded, whereas TE events occurred in 1.4% of low-risk CHADS(2) subjects. When expressed as a scoring system, the CHA2DS2-VASc showed an increase in TE rate with increasing scores (P value for trend = .003).

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    Calculations alone should never dictate patient care, and are no substitute for professional judgement. See our full disclaimer.

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