CHADS2 Score Calculator
Use this calculator to determine a patient's CHADS2 score, which estimates the risk of stroke in patients with non-valvular atrial fibrillation.
(1 point)
(1 point)
(1 point)
(1 point)
(2 points)
Understanding the CHADS2 Score
The CHADS2 score is a clinical prediction rule for estimating the risk of stroke in patients with non-valvular atrial fibrillation (AFib). It was developed to help clinicians decide whether a patient with AFib should receive antithrombotic therapy (e.g., anticoagulants) to prevent stroke.
Components of the CHADS2 Score:
- C – Congestive Heart Failure (1 point): A history of heart failure, indicating reduced heart function.
- H – Hypertension (1 point): A history of high blood pressure, which is a significant risk factor for stroke.
- A – Age ≥ 75 years (1 point): Older age is independently associated with an increased risk of stroke.
- D – Diabetes Mellitus (1 point): Diabetes can damage blood vessels and increase stroke risk.
- S2 – Prior Stroke, TIA, or Thromboembolism (2 points): A history of these events is the strongest predictor of future stroke.
Interpreting the CHADS2 Score:
The total score ranges from 0 to 6. A higher score indicates a greater risk of stroke. Here's a general interpretation:
- Score 0: Low risk of stroke.
- Score 1: Low to moderate risk of stroke.
- Score ≥ 2: Moderate to high risk of stroke, often warranting anticoagulant therapy.
For example, a patient with a CHADS2 score of 0 has an annual stroke risk of about 1.9%, while a patient with a score of 6 has an annual stroke risk of about 18.2% without antithrombotic therapy.
Clinical Significance:
The CHADS2 score helps guide treatment decisions. Patients with higher scores are typically recommended for oral anticoagulation (e.g., warfarin, DOACs) to significantly reduce their stroke risk. However, it's important to note that the CHADS2 score has largely been superseded by the more comprehensive CHA2DS2-VASc score, which includes additional risk factors like vascular disease, age 65-74, and female sex, providing a more nuanced risk assessment.
Important Disclaimer:
This calculator is for informational purposes only and should not be used as a substitute for professional medical advice, diagnosis, or treatment. Always consult with a qualified healthcare provider for any health concerns or before making any decisions related to your health or treatment.
Examples of CHADS2 Score Calculation:
Example 1: A 68-year-old patient with hypertension and diabetes, but no history of CHF, stroke, or TIA.
- Congestive Heart Failure: No (0 points)
- Hypertension: Yes (1 point)
- Age ≥ 75 years: No (0 points)
- Diabetes Mellitus: Yes (1 point)
- Prior Stroke/TIA/Thromboembolism: No (0 points)
- Total CHADS2 Score: 1 + 1 = 2
Example 2: An 80-year-old patient with a history of congestive heart failure and a prior TIA, but no hypertension or diabetes.
- Congestive Heart Failure: Yes (1 point)
- Hypertension: No (0 points)
- Age ≥ 75 years: Yes (1 point)
- Diabetes Mellitus: No (0 points)
- Prior Stroke/TIA/Thromboembolism: Yes (2 points)
- Total CHADS2 Score: 1 + 1 + 2 = 4