Cardiology
ORBIT Bleeding Score
Bleeding risk on anticoagulation in AF.
Education and reference only. Not a substitute for clinical judgement, local policy or product labelling. Always verify before clinical use. Values are calculated in your browser and never stored.
Background
The ORBIT bleeding score estimates the risk of major bleeding in patients with atrial fibrillation taking anticoagulation. It was developed from a large real-world AF registry as a simpler alternative to earlier bleeding scores. Five readily available factors contribute: Anaemia or low haemoglobin (men <13, women <12 g/dL) scoring 2, Age >74 scoring 1, Bleeding history scoring 2, Renal impairment (eGFR <60) scoring 1, and concurrent antiplatelet Treatment scoring 1, for a maximum of 7.
Interpreting the result
A score of 0–2 is low bleeding risk, 3 is medium risk, and 4–7 is high risk, with the predicted rate of major bleeding rising across these bands. The score is intended to inform a discussion about bleeding and to direct attention to modifiable risk factors, rather than to withhold anticoagulation. Where stroke risk warrants anticoagulation, a high bleeding score should trigger risk-factor optimisation and closer follow-up rather than refusal of therapy.
Advice
Use to inform discussion and modifiable-risk management, not to withhold anticoagulation where stroke risk warrants it.
Worked example
A 78-year-old man with anaemia (haemoglobin 12 g/dL) and an eGFR of 50, also taking aspirin: Anaemia (2) + Age >74 (1) + Renal impairment (1) + antiplatelet (1) = 5. This is high bleeding risk, prompting review of the antiplatelet, investigation of the anaemia and careful shared decision-making.
Pearls / pitfalls
- A high score is a reason to address modifiable bleeding factors and follow up closely, not to withhold anticoagulation when stroke risk is significant.
- Anaemia and a prior bleed are the most heavily weighted items and dominate the result.
- It does not capture all bleeding factors (for example uncontrolled hypertension or alcohol excess) — assess these separately.
- Reassess periodically, as renal function, anaemia and concomitant antiplatelet use can change over time.
Evidence & validation
Derived and validated by O'Brien and colleagues using the ORBIT-AF registry and an external anticoagulation trial population, where it discriminated major-bleeding risk at least as well as older tools. It is one of several bleeding scores referenced in AF management discussions.
Frequently asked questions
Does a high ORBIT score mean I should stop anticoagulation?
No. A high score flags greater bleeding risk and should prompt correction of modifiable factors and closer monitoring. If the stroke risk justifies anticoagulation, the score is used to manage rather than withhold treatment.
How does ORBIT compare with HAS-BLED?
Both estimate major bleeding risk in AF, but ORBIT uses five mostly objective, readily available variables. Studies suggest comparable or slightly better discrimination, though either can be used to support shared decision-making.
What counts as anaemia for this score?
A haemoglobin below 13 g/dL in men or below 12 g/dL in women. Anaemia scores two points and is one of the strongest contributors to the total.
Does the score predict stroke risk?
No. ORBIT only estimates bleeding risk. Stroke and thromboembolism risk in AF is assessed separately, typically with CHA₂DS₂-VASc.
References
- O'Brien EC, Simon DN, Thomas LE, et al. The ORBIT bleeding score: a simple bedside score to assess bleeding risk in atrial fibrillation. Eur Heart J. 2015;36(46):3258–3264.
- Hindricks G, et al. 2020 ESC Guidelines for the diagnosis and management of atrial fibrillation. Eur Heart J. 2021.
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