Legacy CHADS₂ Model • See CHA₂DS₂-VASc for current guidelines
Risk Triage Ready
Select clinical history to see statistical annual risk.
Guidelines & Evidence
Verified
Last Review: 2026-07-17
When to Use
Clinical Use
Initial stroke risk stratification for patients with non-valvular atrial fibrillation.
Identifying high-risk patients who require oral anticoagulation.
Historical comparison for longitudinal patient tracking.
Guideline Note
While CHADS₂ was the gold standard for over a decade, the 2020 ESC and 2023 ACC/AHA guidelines now prefer the CHA₂DS₂-VASc score for its better sensitivity in identifying "truly low-risk" patients.
How it Works
Scoring variables
| C: Congestive Heart Failure | 1 pt |
| H: Hypertension | 1 pt |
| A: Age ≥ 75 | 1 pt |
| D: Diabetes Mellitus | 1 pt |
| S₂: Prior Stroke or TIA | 2 pts |
Interpretation of Risk
| Score 0 | 1.9% annual risk (Low) |
| Score 1 | 2.8% annual risk (Intermediate) |
| Score 2+ | 4.0% - 18.2% annual risk (High) |
Clinical Pearls
The CHADS₂ "Gray Zone"
The major limitation of CHADS₂ is that many patients categorized as "low risk" (score of 0 or 1) still have a stroke rate of nearly 2% per year. This led to the development of the more sensitive CHA₂DS₂-VASc model.
Key Pearl
Prior Stroke or TIA is the single strongest predictor of a recurrent event, which is why it receives a double weight (2 points) in this and subsequent models.
Next Steps
Management Recommendations
01
Score 0: Low risk. Aspirin used to be recommended, but now "no treatment" is often preferred if the CHA₂DS₂-VASc is also 0.
02
Score 1: Intermediate risk. Consider oral anticoagulation (DOAC preferred) or aspirin based on patient preference.
03
Score ≥ 2: High risk. Oral anticoagulation is strongly recommended unless absolute contraindications exist.
The Evidence
Primary Derivation
Validation of clinical classification schemes for predicting stroke: results from the National Registry of Atrial Fibrillation.
Gage BF et al. • JAMA.. 2001;n=1,733. Combined the AFI and SPAF models into the modern CHADS₂ score.
Origins & History
Combining the Evidence
Before 2001, doctors used multiple competing models (AFI and SPAF) to guess stroke risk. Dr. Brian Gage and his team performed a meta-analysis to create a single, easy-to-remember mnemonic. CHADS₂ dominated cardiology for 15 years before being refined into the VASc model we use today.
Last Comprehensive Review: 2026-07-17