How it's calculated
Points are added across 8 stroke risk factors, weighted 1 or 2 points each, for a total of 0-9. Higher scores correspond to higher annual stroke risk and a stronger case for anticoagulation.
Approximate annual stroke risk by score
| Score | Annual stroke risk |
|---|---|
| 0 | 0% |
| 1 | 1.3% |
| 2 | 2.2% |
| 3 | 3.2% |
| 4 | 4.0% |
| 5 | 6.7% |
| 6 | 9.8% |
| ≥7 | 9.6–15.2% |
Clinical use
- CHA₂DS₂-VASc is used to decide whether a patient with non-valvular atrial fibrillation should be offered oral anticoagulation to prevent stroke.
- A score of 0 in men (or 1 in women, from sex alone) is generally considered low risk, where anticoagulation is usually not recommended; a score of ≥1 in men (≥2 in women) generally favours anticoagulation.
- It should be weighed alongside a bleeding-risk assessment (e.g. HAS-BLED) — a high stroke risk score doesn't automatically override a very high bleeding risk, but usually still favours anticoagulation with bleeding-risk mitigation rather than withholding it.
- Female sex alone (in an otherwise zero-risk patient) is generally not considered a sufficient reason for anticoagulation by itself — current guidance treats it as a risk-modifying factor rather than the sole trigger.
Frequently asked questions
What is the CHA₂DS₂-VASc score used for?
It estimates the annual risk of stroke in a patient with atrial fibrillation and is the standard tool used to decide whether oral anticoagulation should be recommended.
What CHA₂DS₂-VASc score requires anticoagulation?
General guidance recommends anticoagulation at a score of 1 or more in men and 2 or more in women, while a score of 0 in men (or 1 in women, from sex alone) is usually considered low enough risk that anticoagulation isn't routinely recommended.
Does the CHA₂DS₂-VASc score replace bleeding risk assessment?
No — it should be considered alongside a bleeding risk score like HAS-BLED. A high bleeding risk doesn't usually mean withholding anticoagulation outright, but prompts closer monitoring and mitigation of modifiable bleeding risk factors.
Why does female sex add a point?
Female sex is an independent risk factor for stroke in atrial fibrillation, but current guidance treats it as a risk-modifying factor rather than a standalone indication for anticoagulation on its own.
References
- Lip GY, et al. Refining clinical risk stratification for predicting stroke and thromboembolism in atrial fibrillation. Chest. 2010;137:263-272.
- Hindricks G, et al. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation. Eur Heart J. 2021;42:373-498.
- January CT, et al. 2019 AHA/ACC/HRS Focused Update on Atrial Fibrillation. Circulation. 2019;140:e125-e151.