CHADS₂ Score for Atrial Fibrillation Stroke Risk

What is CHADS2?

CHADS2 is a clinical prediction rule that is used to measure the stroke risk in patients suffering from non-rheumatic atrial fibrillation (AF).

Atrial Fibrillation: This is the condition when atria (the upper chamber of the heart) beat out of rhythm ultimately causing insufficient pumping of blood to the body, causing a fast heart rate with thumping sensation in the heart. This irregular heart rate can cause heart palpitation, fatigue and breathe shortness. 

The total number of CHADS2 is 6, with 5 different risk factors involved for each point.

Here is the abbreviation of each letter with points:

  • (C) Congestive heart failure (1 point)
  • (H) Hypertension: blood pressure consistently above 140/90 mmHg (or treated hypertension on medication) (1 point)
  • (A) Age ≥75 years (1 point)
  • (D) Diabetes mellitus (1 point)
  • (S2) Prior Stroke or TIA or Thromboembolism (2 points)

The score predicts stroke risk on an annual basis. CHADS2 0 predicts the annual risk is about 1.9% which is the lowest and CHADS  score of 6 which means the risk is highest about 18.2 %.  

Every risk factor contributes one point except previous stroke or TIA which contributes 2 points in the total score.

CHADS2 Score Stroke Risk % 95% CI
0 1.9 1.2 - 3.0
1 2.8 2.0 - 3.8
2 4.0 3.1 - 5.1
3 5.9 4.6 - 7.3
4 8.5 6.3 - 11.1
5 12.5 8.2 - 17.5
6 18.2 10.5 - 27.4

How to Calculate of CHADS2 score using online calculator

CHADS2 score calculation requires some risk factor knowledge. Our online Chads calculator is simple and easy to use. All you need is to fulfill the required fields to get the required result.

Just putting the information in the fields and the score will generate after you click on the “calculate” button you will get the results in seconds. The results can be used by the doctors to understand whether you need anticoagulant treatment or not.


Every risk factor increases the risk of stroke in persons with atrial fibrillation. The score is then used to predict the diagnosis a person required.

Here are the scores and particular treatment according to them:

If the score is 0 for male and 1 for females

Risk: Low

Anticoagulant therapy: No anticoagulant therapy

Consideration: Normal value and considered not anticoagulant therapy needed

If the score is 1 for males 

Risk: Moderate

Anticoagulant therapy: Oral anticoagulant therapy is considered

Consideration: consider inpatient or outpatient with proper care

If the score is 2 or greater

Risk: High

Anticoagulant therapy: Oral anticoagulant is suggested

Consideration: Oral anticoagulant, with well-controlled Vitamin K Antagonist (VKA, e.g. warfarin with time in therapeutic range >70%), or a non-VKA Oral Anticoagulant (NOAC, e.g. dabigatran, rivaroxaban, edoxaban or apixaban)


Stroke assessment includes bleeding risk assessment. This assessment can be done by validating bleeding risk score e.g. HEMORR2HAGES or HAS-BLED score.

HAS-BLED is recommended in the guidelines to identify bleeding risk in patients with bleeding risk factors such as hypertension, concomitant aspirin/NSAID, use labile INRS or using an excess of alcohol. 

Other factors involved in stroke risk


Infections contribute a lot to stroke risk. Any kind of infection can increase stroke risk in patients. Examinations and case-study show that chronic infections such as chronic bronchitis, periodontitis can increase the risk and infections with Helicobacter pylori, Chlamydia pneumoniae or Cytomegalovirus also increases the stroke risk.

However, there is a modified version of the CHADS2 score which is the CHA2DS2-VASc score. This version has replaced CHA2DS2 and is used by most of the labs and clinics to measure stroke risk as it includes additional stroke risk that precisely measures the risk than CHADS2.

The risk factor in CHA2DS2-VASc includes:

  • Congestive heart failure (or left ventricular systolic dysfunction) (C)    
  • Hypertension: blood pressure consistently above 140/90 mmHg (or treated hypertension on medication) (H)
  • Age ≥75 years (A2)
  • Diabetes Mellitus (D)
  • Prior Stroke or TIA or thromboembolism (S2)
  • Vascular disease (V)
  • Age 65–74 years (A)
  • Sex category (i.e. female sex) (Sc)

Vascular diseases such as peripheral artery disease, myocardial infarction, an aortic plaque with age between 65-74 years and sex category are the factor that is included in the CHA2DS2-VASc. Each risk factor contributes 1 point except prior stroke, and age above or equivalent to 75 contribute 2 points.

For stroke measurement, this score is precise and used everywhere nowadays.

You can check our CHA2DS2-VASc score calculator to check your stroke risk more accurately.

CHA2DS2-VA Sc Score Stroke Risk % 95% CI
0 0 -
1 1.3 -
2 2.2 -
3 3.2 -
4 4.0 -
5 6.7 -
6 9.8 -
7 9.6 -
8 12.5 -
9 15.2 -

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