Calculates your stroke risk in atrial fibrillation and tells you whether anticoagulation is recommended — based on 2023 ACC/AHA guidelines. Tick the boxes that apply. Done in 30 seconds.
Lip GYH et al., Chest 2010 · Non-valvular atrial fibrillation · ACC/AHA 2023
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| Score | Annual stroke risk | Recommendation |
|---|
The CHA₂DS₂-VASc score (also written as CHADS2-VASc or CHADS VASc) estimates the annual stroke risk in patients with non-valvular atrial fibrillation. It tells you and your doctor whether anticoagulation is likely to do more good than harm.
Published by Lip GYH et al. in Chest in 2010, it replaced the original CHADS₂ score by adding 3 extra variables: vascular disease, age 65–74, and female sex. The result was a better tool for identifying patients who genuinely don't need anticoagulation.
A score of 0 in men means roughly 0% annual stroke risk. At score 6, that's around 9.8% per year — nearly 1 in 10 — without anticoagulation.
Score ≥2 in men (or ≥3 in women) is a Class I indication for a DOAC per 2023 ACC/AHA guidelines. The decision also weighs bleeding risk and kidney function.
Female sex adds 1 point but doesn't independently trigger anticoagulation. A woman with a score of 1 (female sex only) is still low risk per ESC 2020 guidelines.
The full form of CHA₂DS₂-VASc breaks down as follows:
Maximum possible score is 9. Only one age category applies — if a patient is 75 or older, they score 2 points for age and do not also score the 65–74 category.
There's no "normal" CHA₂DS₂-VASc score — any score above 0 represents some degree of elevated stroke risk. Here's how to interpret the score:
| Score | Annual stroke risk | ACC/AHA 2023 recommendation |
|---|---|---|
| 0 (men) / 1 (women, female sex only) | ~0% | Anticoagulation not recommended |
| 1 (men) / 2 (women, excl. female sex only) | ~1.3% | Consider anticoagulation (Class IIb) |
| 2 (men) | ~2.2% | Anticoagulation recommended (Class I) |
| 3 | ~3.2% | Anticoagulation recommended (Class I) |
| 4 | ~4.0% | Anticoagulation recommended (Class I) |
| 5 | ~6.7% | Anticoagulation recommended (Class I) |
| 6 | ~9.8% | Anticoagulation recommended (Class I) |
| 7 | ~9.6% | Anticoagulation recommended (Class I) |
| 8 | ~12.5% | Anticoagulation recommended (Class I) |
| 9 | ~15.2% | Anticoagulation recommended (Class I) |
Source: Lip GYH et al., Swedish registry validation cohort. Chest 2010;137:263–72.
A score of 2 in a male patient is a Class I indication for anticoagulation per 2023 ACC/AHA guidelines — meaning it's strongly recommended, not just optional. The annual stroke risk at this level is approximately 2.2%.
For a female patient, a score of 2 where female sex is the only non-sex point is equivalent to a male score of 1 — classified as Class IIb (consider, don't mandate). A female patient with 2 points from two actual risk factors (not counting female sex) warrants anticoagulation.
In both cases, a DOAC (apixaban, rivaroxaban, dabigatran, or edoxaban) is preferred over warfarin for non-valvular AFib.
The original CHADS₂ score (Gage BF et al., 2001) had 5 criteria and a maximum of 6 points. It was decent at spotting high-risk patients but terrible at identifying low-risk ones — around 60% of AFib patients fell into the "moderate risk" category with CHADS₂, leaving the treatment decision unclear.
CHA₂DS₂-VASc extended the score to 0–9 by adding vascular disease, age 65–74, and female sex. The extra resolution means fewer patients land in the ambiguous middle. A CHA₂DS₂-VASc score of 0 in men has an annual stroke rate close to 0% in validation studies — genuinely safe to withhold anticoagulation.
Most major guidelines — including ACC/AHA, ESC, and CCS — replaced CHADS₂ with CHA₂DS₂-VASc between 2012 and 2016. CHADS₂ is still used in some older literature and clinical systems but is no longer guideline-preferred.
Any score of 2 or above in men (or 3 or above in women) is considered high enough to warrant anticoagulation per ACC/AHA 2023 guidelines. But in practical terms, scores of 5 and above represent serious risk — at score 5, the annual stroke probability is around 6.7%, and by score 9 it reaches 15.2%.
A score of 7–9 in particular is in territory where the stroke risk so clearly outweighs the bleeding risk that anticoagulation is unambiguous — the clinical conversation shifts from "should we anticoagulate?" to "which DOAC and what dose?"
The CHA₂DS₂-VASc score tells you the stroke risk. The HAS-BLED score tells you the bleeding risk. You need both before making an anticoagulation decision.
HAS-BLED was published by Pisters R et al. in Chest in 2010 — the same year as CHA₂DS₂-VASc. It estimates 1-year major bleeding risk in patients with AFib on or being considered for anticoagulation.
Maximum HAS-BLED score is 9. A score of 3 or above is considered high bleeding risk and signals the need for careful monitoring after anticoagulation begins — not automatic exclusion from it.
| HAS-BLED score | 1-year major bleeding risk | Clinical action |
|---|---|---|
| 0–1 | ~1.0% | Low risk — anticoagulate if CHA₂DS₂-VASc warrants |
| 2 | ~1.9% | Moderate risk — proceed with monitoring |
| 3 | ~3.7% | High risk — address modifiable factors, monitor closely |
| 4 | ~8.7% | High risk — correct modifiable factors before anticoagulating |
| ≥5 | >9.1% | Very high — expert review recommended |
A high HAS-BLED score should prompt correcting modifiable risk factors (controlling blood pressure, stopping NSAIDs, reducing alcohol) — not automatically withholding anticoagulation. The stroke risk from AFib usually still outweighs the bleeding risk.
The standard workflow in AFib management is to calculate both scores:
A high HAS-BLED score in isolation is not a contraindication to anticoagulation. At a CHA₂DS₂-VASc score of 4 (4.0% annual stroke risk) with a HAS-BLED of 3 (3.7% bleeding risk), anticoagulation still provides net clinical benefit in most patients.
The ORBIT score (Outcomes Registry for Better Informed Treatment of Atrial Fibrillation) is a newer alternative bleeding risk tool for AFib patients. It uses 5 criteria:
ORBIT scores 0–2 = low risk (~2.4% bleeding/year), 3 = medium (~4.7%), 4–7 = high (~8.1%). Some studies show ORBIT performs comparably or slightly better than HAS-BLED for predicting bleeding on DOACs specifically. HAS-BLED remains more widely used in clinical practice and guidelines.
The 2024 ESC Guidelines on atrial fibrillation replaced CHA₂DS₂-VASc with a simplified version: CHA₂DS₂-VA. The new score removes female sex as a scoring criterion, based on evidence that female sex is a risk modifier rather than an independent stroke risk factor.
CHA₂DS₂-VA has a maximum score of 8 (not 9). The anticoagulation thresholds shift accordingly: score ≥2 in all patients (regardless of sex) triggers anticoagulation recommendation.
The ACC/AHA 2023 guidelines still use CHA₂DS₂-VASc. The ESC 2024 guidelines now recommend CHA₂DS₂-VA. Which score to use depends on which guideline your clinical system follows. If you're in the US, CHA₂DS₂-VASc and the ACC/AHA 2023 thresholds apply.
Your CHA₂DS₂-VASc score is one input. Your doctor will also consider:
Per 2023 ACC/AHA guidelines: score ≥2 in men, or ≥3 in women, is Class I (recommended). Score 1 in men (or 2 in women excluding female sex as sole point) is Class IIb (consider). Score 0 in men or 1 in women (female sex only) — anticoagulation not recommended.
The score ranges from 0 to 9. There's no "normal" — score 0 in men means very low stroke risk, score 9 means approximately 15% annual stroke risk. Any score above 1 in men (or 2 in women) warrants anticoagulation per guidelines.
Congestive heart failure, Hypertension, Age ≥75 (2 points), Diabetes, Stroke/TIA (2 points), Vascular disease, Age 65–74, Sex category female. The subscript numbers indicate variables worth 2 points rather than 1.
Clinically, any score ≥2 in men (or ≥3 in women) is "high enough" to warrant anticoagulation. Practically, scores of 5 and above represent serious annual stroke risk of 6.7% or more. Scores 7–9 are in territory where the anticoagulation decision is unambiguous.
HAS-BLED estimates 1-year major bleeding risk in AFib patients on or being considered for anticoagulation. It's used alongside CHA₂DS₂-VASc to make the full anticoagulation decision. A score ≥3 means high bleeding risk and warrants closer monitoring — not automatic exclusion from anticoagulation.
No. CHA₂DS₂-VASc applies to non-valvular AFib only. Patients with moderate-to-severe mitral stenosis or a mechanical heart valve are at high enough stroke risk that anticoagulation is recommended regardless of their score — and warfarin (not DOACs) is the preferred agent in those cases.
Yes, female sex adds 1 point. But a woman with score 1 where female sex is her only point is still low risk. ESC 2020 guidelines clarified that female sex is a risk modifier, not an independent stroke predictor. The 2024 ESC guidelines removed it from scoring entirely (CHA₂DS₂-VA).
CHADS₂ (2001) has 5 criteria, max score 6. CHA₂DS₂-VASc (2010) has 8 criteria, max score 9. CHA₂DS₂-VASc is better at identifying truly low-risk patients, putting fewer people in the ambiguous middle. Most guidelines replaced CHADS₂ between 2012 and 2016.