HAS - BLED score

Last edited 05/2021 and last reviewed 08/2023

The HAS-BLED is a therapeutic bleeding risk stratification score for those on oral anticoagulants in atrial fibrillation (1).

HAS-BLED score for bleeding risk on oral anticoagulation in atrial fibrillation

• score of 3 or more indicates increased one year bleed risk on anticoagulation sufficient to justify caution or more regular review
  • risk is for intracranial bleed, bleed requiring hospitalization or a haemoglobin drop > 2g/L or that needs transfusion

HAS-BLED score may underestimate bleeding risk in a subset of atrial fibrillation patients (2)

• several conditions present a challenge in decision making, including
  • chronic subdural hematoma,
  • cerebral vascular malformations,
  • gastrointestinal conditions that predispose to bleeding and may be difficult to treat (Crohn’s disease, angiodysplasia),
  • hematological disorders of coagulation
  • cerebral amyloid angiopathy (CAA), which involves beta-amyloid deposition in cerebral blood vessels, is especially relevant in older people with atrial fibrillation and is a common cause of anticoagulant related intracranial hemorrhage
    • estimated a 7.4% annual risk of CAA related recurrent intracranial hemorrhage, comparable in many older atrial fibrillation patients to the risk of ischemic stroke if untreated
    • CAA most often manifests with lobar hemorrhage but can also be detected in patients without symptoms with hemosiderin sensitive magnetic resonance imaging (MRI) sequences
      • a HAS-BLED score does not account for such asymptomatic MRI lesions, the score may underestimate bleeding risk in this population
      • no prospective trials of treatment approaches in this patient population have been conducted, but warfarin should generally be avoided in favor of DOACs or left atrial appendage closure if the ischemic stroke risk justifies treatment

NICE have suggested that the ORBIT bleeding risk score should be used (in comparison to other bleeding risk scoring systems such as HAS-BLED) in assessing the risk of bleeding when a patient commences, or is under review, regarding anticoagulation therapy in atrial fibrillation (3).

NICE state that "because evidence shows that it has a higher accuracy in predicting absolute bleeding risk than other bleeding risk tools. Accurate knowledge of bleeding risk supports shared decision making and has practical benefits, for example, increasing patient confidence and willingness to accept treatment when risk is low and prompting discussion of risk reduction when risk is high. Although ORBIT is the best tool for this purpose, other bleeding risk tools may need to be used until it is embedded in clinical pathways and electronic systems..."

Click here for online ORBIT risk calculator

Reference:

• 1) Pisters R, Lane DA, Nieuwlaat R, de Vos CB, Crijns HJ, Lip GY. A novel user-friendly score (HAS-BLED) to assess one-year risk of major bleeding in atrial fibrillation patients: The Euro Heart Survey. Chest. 2010 Mar 18
• 2) Ponamgi SP et al. Screening and management of atrial fibrillation in primary care. BMJ 2021;372:mn379 http://dx.doi.org/10.1136/bmj.mn379
• 3) NICE (April 2021). Atrial fibrillation: diagnosis and management.