HAS-BLED Score Calculator

How does this HAS-BLED score calculator work?

This is a health tool designed to work as a major bleeding risk score, stratifying patients with atrial fibrillation in terms of anticoagulation therapies. The study describes major bleeding as event needing hospitalization, involving intracranial bleeding, haemoglobin decrease of more than 2 g/L and/or need for transfusion secondary to bleeding.

The first part of the study noted the clinical data of the patients while the follow up draw the research and provided conclusion on the survival of patients and notable major adverse cardiac events such as major bleeding.

The score name comes from the acronym of the criteria assessed, as described below by referring to the HAS-BLED score calculator. Each of these criteria are awarded 1 or 0 points, 1 for positive answers and 0 for negative answers.

■ Hypertension – BP systolic with values above 160 mmHg and untreated.

■ Abnormal liver and renal function – biochemical evidence creatinine higher than 2.6 mg/dL (200 mmol/L), bilirubin higher 2x or AST/ALT/AP higher 3x normal, under dialysis, transplant, abnormal hepatic function, chronic hepatic disease.

■ Stroke history – family or personal history of vascular events provoked or unprovoked events.

■ Bleeding predisposition – history of major bleeding event, a predisposition based on clinical date or because of treatment with antiplatelet agents, NSAIDs etc.

■ Labile INRs – unstable or very high INRs with a time in therapeutic range of less than 60%.

■ Elderly age – above 65 years, that is considered to be one of the risk factors in atrial fibrillation.

■ Drugs/Alcohol usage – more than 7 drinks per week and/ or substance abuse present or in history.

HAS-BLED score interpretation

The tool allows for a practical and quick testing and provides a 1 year risk score percentage. Guidelines state that scores higher than 3 should be clinically monitored regularly after the oral anticoagulation therapy has begun.

The score range is between 0 an 9, with scores of above 6 being considered so rarely met that they are often not considered in studies and its major bleeding risk is not accounted for in research. However, it is considered to be above the HAS-BLED score 5 risk percentage i.e. 9.10%.

The conclusions of the research were that there is a direct link between the presence and severity of the risk factors and the increase in major bleeding events in the studied patients.

However, one of the criticisms attributed to the model is that it only provides a percentage risk and not a category such as low, medium and high risk.

Clinicians are advised to take this score in consideration and also the CHADS2 calculator to help them in weighing the benefits and contraindications of initiating anticoagulant therapy in their patients.

Atrial fibrillation guidelines

The HAS-BLED score is often used alongside the CHA2DS2-VASc score to evaluate and stratify risk of stroke in patients with atrial fibrillation because the risk factors that contribute to stroke in patients with anticoagulation treatment are similar to the factors for major bleeding risk.

Atrial fibrillation is a heart condition that causes irregularities in the heart beat and usually abnormally fast heart rates, considerably higher than 100 bpm.

Some of the most common symptoms include the feeling of heart palpitations, dizziness, shortness of breath, chest pain, fainting, tiredness and heart beat irregularities lasting for seconds up to minutes at once. In some cases, there are no evident symptoms although an underlying condition exists.

There are four categories to classify AF by taking into account the frequency of the palpitation episodes:

■ 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.

Treating AF is very important as it prevents risk of stroke and other cardiac events and the main therapeutic ways involve either medication to control the heart rate, rhythm or prevent a stroke. Cardioversion or catheter ablation can also be employed in different situations in order to regularize the heart beat.

References

1) Pisters R, Lane DA, Nieuwlaat R, de Vos CB, Crijns HJ, Lip GY. (2010) 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; 138(5):1093-100

2) Lip GY, Frison L, Halperin JL, Lane DA. (2011) 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. 11; 57(2):173-80

3) Gage BF, Yan Y, Milligan PE, Waterman AD, Culverhouse R, Rich MW, Radford MJ. (2006) Clinical classification schemes for predicting hemorrhage: results from the National Registry of Atrial Fibrillation (NRAF). Am Heart J. 2006 Mar; 151(3):713-9.

4) Camm AJ, Kirchhof P, Lip GY, et al. (2010) 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; 31(19):2369-2429.

5) Lip GY, Andreotti F, Fauchier L, et al. (2011) 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; 13:723-746.