In the text below the calculator there is more information on the score and on the original study.
The HAS-BLED score is a bleeding risk classification tool addressed to patients diagnosed with atrial fibrillation and due to start anticoagulation therapy.
The study defines major bleeding as a condition that requires hospitalization, involves intracranial bleeding, a haemoglobin decrease of more than 2 g/L and/or need for transfusion secondary to bleeding.
The nine items in the score address major bleeding risk factors such as hypertension, labile INR, patient history of stroke, liver or kidney disease.
If present, each of the 9 risk factors in the HAS-BLED score is awarded 1 point. Therefore, the score result varies in theory between 0 and 9.
However, in practice, values above 6 have not been achieved, therefore a percentage of risk has not been accurately established, although known to be higher than 9.10%.
The correlation between score results and major bleeding risk can be found in the table below:
|Score||Risk of major bleeding|
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The scoring system explained
This score is recommended in the assessment of patients diagnosed with atrial fibrillation in order to stratify bleeding risk, before anticoagulation therapy is initiated.
A major bleeding event requires hospitalization, involves a haemoglobin decrease of more than 2 g/L and intracranial bleeding and may require transfusion.
The score is named after the criteria assessed, which can be found in the table below:
|Hypertension history||Systolic blood pressure above 160 mmHg and not under treatment.|
|Renal disease||Creatinine values higher than 2.6 mg/dL (200 mmol/L).|
|Liver disease||Bilirubin two times higher than normal or AST/ALT/AP three times higher than normal. Patient under dialysis, transplant, abnormal hepatic function or chronic hepatic disease.|
|Stroke history||Family or personal history of vascular events provoked or unprovoked.|
|History of major bleeding or predisposition||The predisposition is based on clinical data or because of treatment with antiplatelet agents, NSAIDs etc.|
|Labile INR – high values||Unstable or very high INRs with a time in therapeutic range of less than 60%.|
|Age higher than 65||Elderly patients are at higher risk of bleeding.|
|Under medication that predisposes to bleeding.||Patient is under anticoagulation therapy (e.g. Warfarin).|
|Alcohol or drug usage history||More than 7 drinks per week.|
This model has been criticised for not providing a risk category (such as low, medium or high) alongside the risk percentage.
There are other risk stratification tools, such as the CHADS2, that can be used to weight the benefits and risks of anticoagulant therapy in patients with atrial fibrillation.
The score results vary from 0 to 9 and are associated with a 1-year bleeding risk percentage:
|Score||Risk of major bleeding|
The recommendation is that any patient scoring higher than 3 should be clinically monitored regularly after the oral anticoagulation therapy is initiated.
Scores of 6 and above are considered to be exceptions and are often not considered in studies. Their associated bleeding risk is considerably higher than that of a 5 score, which is 9.10%.
About the study
The score was created by Pisters et al. in 2010, following a study on 3,978 patients from the Euro Heart Survey. These patients were diagnosed with atrial fibrillation and a complete follow up plus multivariate analysis on potential bleeding risk factors was performed.
53 major bleeding events occurred during the 1-year follow up period and the annual bleeding rate increased with increasing risk factors.
The score showed consistent predictive accuracy in several subgroups of the study.
The bleeding score created, the HAS-BLED (Hypertension, Abnormal renal/liver function, Stroke, Bleeding history or predisposition, Labile international normalized ratio, Elderly (>65 years), Drugs/alcohol concomitantly), showed that there is a direct link between the presence and severity of the risk factors and the increase in major bleeding events.
Atrial fibrillation guidelines
AF is a cardiovascular condition in which irregularities in the heart beat can be observed (lasting for seconds up to minutes), usually as abnormally fast heart rates, considerably higher than 100 bpm.
Whilst in some cases, there are no symptoms present, the most common manifestations of AF include: heart palpitations, dizziness, chest pain, shortness of breath, fainting, tiredness and heart beat irregularities.
The frequency of the palpitation events classifies AF in four categories:
■ Paroxysmal atrial fibrillation – episodes varying, stopping in less than 48h without treatment;
■ Persistent atrial fibrillation – episodes lasting longer than seven days without treatment;
■ Long-standing persistent atrial fibrillation – continuous episodes during an entire year;
■ Permanent atrial fibrillation – AF present all the time.
AF patients are at risk of stroke and other major cardiac events and treatment should be initiated as soon as the condition is diagnosed.
Medication usually controls the heart rate and rhythm and may prevent a stroke but also comes with other risks (e.g. bleeding risk), that need to be managed. In some cases, cardioversion or catheter ablation may be used to regularize the heart rate.
Pisters R, Lane DA, Nieuwlaat R, de Vos CB, Crijns HJ, Lip GY. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation: the Euro Heart Survey. Chest. 2010; 138(5):1093-100.
Lip GY, Frison L, Halperin JL, Lane DA. Comparative validation of a novel risk score for predicting bleeding risk in anticoagulated patients with atrial fibrillation: the HAS-BLED (Hypertension, Abnormal Renal/Liver Function, Stroke, Bleeding History or Predisposition, Labile INR, Elderly, Drugs/Alcohol Concomitantly) score. J Am Coll Cardiol. 2011; 57(2):173-80.
1. Camm AJ, Kirchhof P, Lip GY, et al. Guidelines for the management of atrial fibrillation: The task force for the management of atrial fibrillation of the European Society of Cardiology (ESC). Eur Heart J. 2010; 31(19):2369-2429.
2. Lip GY, Andreotti F, Fauchier L, et al. Bleeding risk assessment and management in atrial fibrillation patients: a position document from the European Heart Rhythm Association, endorsed by the European Society of Cardiology Working Group on Thrombosis. Europace. 2011; 13:723-746.
Objective: Risk Stratification
No. Of Items: 9
Year Of Study: 2010
Published On: June 6, 2017 · 07:12 AM
Last Checked: June 6, 2017
Next Review: June 6, 2023