CHADS2 Score Calculator
Your CHADS2 Score:
0Interpretation of Stroke Risk:
CHADS2 score of 0: Low risk (approx. 0-1.5% stroke per year)
CHADS2 score of 1: Low to Moderate risk (approx. 1.3-3% stroke per year)
CHADS2 score of 2: Moderate risk (approx. 2.5-4% stroke per year)
CHADS2 score of 3-4: High risk (approx. 4-10% stroke per year)
CHADS2 score of 5-6: Very High risk (approx. 10-18% stroke per year)
Note: This is a simplified calculator. Consult a healthcare professional for definitive advice.
Understanding the CHADS2 Score and Stroke Risk
The CHADS2 score is a clinical prediction tool used to assess the risk of stroke in patients with atrial fibrillation (AF). Atrial fibrillation is a common heart rhythm disorder where the upper chambers of the heart quiver abnormally, leading to inefficient blood flow. This can cause blood clots to form in the heart, which can then travel to the brain and cause a stroke.
The CHADS2 scoring system was developed to help clinicians stratify this risk and guide treatment decisions, particularly regarding the use of anticoagulation (blood-thinning medications). A higher CHADS2 score indicates a higher risk of stroke.
Components of the CHADS2 Score:
Each of the following risk factors contributes points to the total CHADS2 score:
- C – Congestive Heart Failure: 1 point if present.
- H – Hypertension: 1 point if blood pressure is consistently elevated (typically defined as systolic BP > 140 mmHg or diastolic BP > 90 mmHg).
- A – Age: 1 point if the patient is 65-74 years old, and 2 points if the patient is 75 years or older. (Note: This calculator simplifies this to Age ≥ 75 for 2 points as per common CHADS2 usage).
- D – Diabetes Mellitus: 1 point if the patient has diabetes.
- S – Prior Stroke or Transient Ischemic Attack (TIA): 2 points if the patient has a history of stroke or TIA.
The 'S' for Stroke/TIA and the 'A' for Age ≥ 75 years are weighted more heavily (2 points each) due to their significant association with increased stroke risk.
How the CHADS2 Score is Calculated:
To calculate the CHADS2 score, a healthcare provider assesses the patient for the presence of each of these five risk factors. Each factor is assigned a point value (0, 1, or 2). The individual point values are then summed to obtain the total CHADS2 score, which can range from 0 to 6.
Interpreting the CHADS2 Score:
The total CHADS2 score is used to estimate the annual risk of ischemic stroke:
- CHADS2 Score of 0: Indicates a low annual stroke risk (approximately 0-1.5%). For these patients, the decision on anticoagulation might be less clear-cut, and other factors may be considered.
- CHADS2 Score of 1: Indicates a low to moderate annual stroke risk (approximately 1.3-3%). Anticoagulation is often recommended.
- CHADS2 Score of 2: Indicates a moderate annual stroke risk (approximately 2.5-4%). Anticoagulation is generally recommended.
- CHADS2 Scores of 3-4: Indicate a high annual stroke risk (approximately 4-10%). Anticoagulation is strongly recommended.
- CHADS2 Scores of 5-6: Indicate a very high annual stroke risk (approximately 10-18%). Anticoagulation is highly recommended.
Treatment Implications:
The CHADS2 score is a critical factor in deciding whether a patient with atrial fibrillation should receive anticoagulant therapy (like warfarin, dabigatran, rivaroxaban, or apixaban) or antiplatelet therapy. Generally:
- Patients with a CHADS2 score of 0 may not require anticoagulation, or may be considered for aspirin.
- Patients with a CHADS2 score of 1 are often recommended to receive anticoagulation or aspirin.
- Patients with a CHADS2 score of 2 or higher are typically recommended to receive anticoagulation therapy to significantly reduce their stroke risk.
It's important to note that the CHADS2 score is a simplified tool. Newer scoring systems like CHA2DS2-VASc (which includes vascular disease, female gender, and uses a different age stratification) are now more commonly used as they provide a more refined risk assessment.
Disclaimer: This calculator is for informational purposes only and does not substitute professional medical advice. Always consult with a qualified healthcare provider for diagnosis and treatment recommendations.