HAS-BLED Score
Major bleeding risk assessment for patients on anticoagulation
Calculator
Why use it
Identifies modifiable bleeding risk factors. Guides shared decision-making about anticoagulation. Recommended by ESC and AHA/ACC guidelines alongside CHA₂DS₂-VASc.
About
HAS-BLED estimates the 1-year risk of major bleeding in patients with atrial fibrillation on anticoagulation therapy. It is used alongside CHA₂DS₂-VASc to weigh stroke prevention benefit against bleeding risk. A high HAS-BLED score should prompt review of modifiable risk factors, not necessarily avoidance of anticoagulation.
When to use
- Atrial fibrillation patients being considered for anticoagulation
- Annual reassessment of patients on chronic anticoagulation
- After a bleeding event to re-evaluate risk-benefit
Formula
Pearls & pitfalls
- HAS-BLED ≥ 3 means "high risk" but does NOT mean "do not anticoagulate".
- Focus on MODIFIABLE factors: uncontrolled BP, labile INR, drugs (NSAIDs, antiplatelets), alcohol.
- Labile INR only applies to VKA (warfarin) users, not DOACs.
- DOACs generally have lower bleeding risk than warfarin at equivalent HAS-BLED scores.
- The score should be recalculated periodically as risk factors change.
Next steps
Score ≥ 3: High bleeding risk — address modifiable factors (BP control, stop unnecessary NSAIDs/antiplatelet, reduce alcohol, optimize INR control). A high score alone should NOT preclude anticoagulation when CHA₂DS₂-VASc indicates benefit.
Evidence
Derived from the Euro Heart Survey (Pisters et al., Chest 2010). Validated in multiple AF cohorts. C-statistic ~0.72 for major bleeding prediction. Endorsed by ESC 2020 AF guidelines.
References
- Pisters R et al. A novel user-friendly score (HAS-BLED) to assess 1-year risk of major bleeding in patients with atrial fibrillation. Chest. 2010;138(5):1093-1100. — link