Calculator Inputs
Example Data Table
Sample cases for learning. Do not use as clinical instruction.
| Case | Sex | Age band | CHF | HTN | DM | Prior Stroke/TIA | Vascular | Score | Est. Annual Risk |
|---|---|---|---|---|---|---|---|---|---|
| A | Male | Under 65 | No | No | No | No | No | 0 | ~0.2% |
| B | Female | 65–74 | No | Yes | No | No | No | 3 | ~3.2% |
| C | Male | 75 or older | Yes | Yes | Yes | No | Yes | 6 | ~9.7% |
| D | Female | 75 or older | Yes | Yes | No | Yes | No | 8 | ~10.8% |
Formula Used
This calculator uses the CHA₂DS₂-VASc point system commonly applied to estimate stroke risk in atrial fibrillation. Points are summed across selected factors:
- Congestive heart failure = 1
- Hypertension = 1
- Age 65–74 = 1
- Age ≥75 = 2
- Diabetes mellitus = 1
- Stroke/TIA/embolism history = 2
- Vascular disease = 1
- Sc (sex category female) = 1
Estimated annual stroke risk is mapped from the final score using a commonly cited table. Different studies and guidelines report different rates.
How to Use This Calculator
- Select sex category and the correct age band.
- Tick each clinical factor that applies to the person.
- Click Calculate Score to view results above.
- Use the breakdown to verify each point was intended.
- Export your result using CSV or PDF buttons.
- Discuss decisions with a qualified clinician.
FAQs
1) What does this score measure?
It estimates stroke risk associated with atrial fibrillation using a point checklist. It does not diagnose AF or predict every cause of stroke.
2) Are the percentage risks exact?
No. Percentages are estimates from population studies and can differ by cohort, treatment, and comorbidities. Use them for discussion, not precision prediction.
3) Why does age add more points at 75?
Stroke risk rises sharply with older age in AF populations, so many scoring systems weight age ≥75 more heavily than age 65–74.
4) Does female sex always increase treatment need?
Not always. Some guidelines treat sex as a modifier and consider other factors first. Always follow local clinical guidance for decisions.
5) Can I use this for people without atrial fibrillation?
This model was designed for AF-related stroke risk discussions. For non‑AF stroke prediction, other validated tools may be more appropriate.
6) What does vascular disease include?
It commonly includes prior myocardial infarction, peripheral arterial disease, or aortic plaque. Confirm definitions used in your clinical setting.
7) Why mention guideline differences?
Risk tools evolve. Some recent guidance uses a variant without sex category. If your clinic uses a different model, match it for consistency.