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ORBIT Bleeding Risk Score for Atrial Fibrillation

Estimates major bleeding risk on anticoagulation for atrial fibrillation.

ORBIT Bleeding Risk Score for Atrial Fibrillation
Age >= 74 years
Reduced haemoglobin/haematocrit or history of anaemia (Hb <12 g/dL or Hct <36% in women; Hb <13 g/dL or Hct <40% in men)
History of major bleeding (gastrointestinal or intracranial)
eGFR < 60 mL/min/1.73 m^2
Concurrent antiplatelet therapy
Result0 points

Approximately 2.4 major bleeding events per 100 patient-years in the derivation cohort.

Bleeding rate
2.4 per 100 patient-years

When to use

  • Estimating bleeding risk when weighing anticoagulation for atrial fibrillation, alongside a thromboembolic risk score such as CHA2DS2-VASc.

Formula

Sum of: age >=74y (1), reduced haemoglobin/haematocrit or anaemia history (2), prior major bleeding (2), eGFR <60 mL/min/1.73m^2 (1), concurrent antiplatelet use (1). Range 0-7.

Pearls and pitfalls

  • Included in the 2023 ACC/AHA/ACCP/HRS atrial fibrillation guideline as an option for bleeding risk assessment.
  • Performed at least as well as HAS-BLED and ATRIA in external comparisons, including in patients on direct oral anticoagulants.

References

  1. O'Brien EC, Simon DN, Thomas LE, et al. Eur Heart J. 2015;36(46):3258-3264.