The HAS-BLED Score: A Validated Tool for Bleeding Risk Assessment in Anticoagulated Patients
The HAS-BLED score is a validated clinical tool for assessing bleeding risk in patients taking anticoagulants, with its primary purpose being to identify patients at high risk for bleeding events who require more frequent monitoring and modification of risk factors, not to withhold anticoagulation. 1
Components of the HAS-BLED Score
The HAS-BLED score includes the following components, with 1 point assigned to each (maximum score of 9):
- H: Hypertension (systolic blood pressure >160 mmHg)
- A: Abnormal renal/liver function (1 point each)
- S: Stroke history
- B: Bleeding history or predisposition
- L: Labile INR (if on warfarin)
- E: Elderly (age >65 years)
- D: Drugs/alcohol concomitantly (1 point each)
Interpretation and Clinical Application
- Score 0-2: Low-moderate bleeding risk
- Score ≥3: High bleeding risk requiring more frequent review and follow-up 1
Evidence Supporting HAS-BLED's Utility
HAS-BLED has demonstrated superior performance compared to other bleeding risk scores:
- It outperforms HEMORR₂HAGES and ATRIA scores in sensitivity (0.53 vs 0.27 for HEMORRHAGES and 0.23 for ATRIA) 1
- It is better at identifying patients at low risk of bleeding compared to newer scores like ABC-bleeding 1
- It is the only bleeding score validated to predict intracranial bleeding specifically 1
- It has been validated across multiple patient populations:
- Patients on vitamin K antagonists
- Patients on direct oral anticoagulants (DOACs)
- Patients on no anticoagulation or antiplatelet therapy
- Different ethnic groups 1
Clinical Decision-Making Algorithm
Calculate both CHA₂DS₂-VASc (stroke risk) and HAS-BLED (bleeding risk) scores 1
For patients with HAS-BLED ≥3:
- Schedule more frequent follow-up (every 4 weeks rather than every 4-6 months) 1
- Address modifiable bleeding risk factors:
- Control hypertension
- Improve INR control if on warfarin
- Discontinue unnecessary antiplatelet agents or NSAIDs
- Reduce alcohol consumption
- Treat reversible causes of renal/liver dysfunction 2
Do NOT withhold anticoagulation solely based on high HAS-BLED score 1
- The net clinical benefit of stroke prevention is often greater in those with high bleeding risk
- A high bleeding risk score should trigger risk factor modification, not anticoagulation discontinuation
Important Clinical Considerations
HAS-BLED has predictive value not only for bleeding but also for cardiovascular events and mortality, highlighting the complex relationship between thrombosis and bleeding 3
Bleeding risk assessment should be performed at every patient contact and is dynamic, requiring regular reassessment 1
In comparative studies, HAS-BLED showed a significant net benefit for predicting any bleeding compared to newer algorithm-based scores like GARFIELD-AF 4
Meta-analyses show HAS-BLED has moderate predictive ability (C-statistic 0.63) for major bleeding in patients on both vitamin K antagonists and DOACs 5
While initially developed for atrial fibrillation patients, HAS-BLED has also shown utility in venous thromboembolism patients, where a score ≥3 indicates significantly increased risk for major bleeding events (OR: 13.05) 6
Common Pitfalls to Avoid
Pitfall #1: Using a high HAS-BLED score as justification to withhold anticoagulation
- Solution: Use the score to identify patients needing closer monitoring and risk factor modification
Pitfall #2: Calculating the score once and never reassessing
- Solution: Bleeding risk is dynamic and should be reassessed at every clinical encounter
Pitfall #3: Focusing only on non-modifiable risk factors
- Solution: Actively address modifiable factors like hypertension, medication interactions, and alcohol use
Pitfall #4: Using HAS-BLED in isolation
- Solution: Always consider both stroke risk (CHA₂DS₂-VASc) and bleeding risk (HAS-BLED) together when making anticoagulation decisions