WardRound

For healthcare professionals. Educational tool only — not a medical device. Verify all results against the current BNF, NICE guidance and local policy, and apply clinical judgement.

Risk scoresCardiology

ORBIT — bleeding risk in AF

Estimates bleeding risk in atrial fibrillation patients considered for anticoagulation — the score NICE NG196 prefers.

ORBIT score

0

Low bleeding risk

Bleeds per 100 patient-years
2.4ORBIT-AF derivation cohort (O'Brien 2015)

Caveats & limitations

  • Derived in the ORBIT-AF registry (predominantly US, warfarin-era); absolute rates differ with DOACs.
  • Use bleeding risk to guide monitoring and modifiable factors, not as a stand-alone reason to withhold anticoagulation.

Evidence & UK guidance

Primary evidence

  • 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.

    PubMedDOI

UK practice

NICE NG196 (2021) recommends ORBIT for assessing bleeding risk in AF because it may be more accurate than HAS-BLED or ATRIA; other tools are acceptable until ORBIT is embedded in practice. As with HAS-BLED, a high score prompts correction of modifiable factors and closer review — not automatic withholding of anticoagulation.

Official resources

Formula and citations last verified: 2026-08-03

Related calculators

CHA₂DS₂-VASc

Estimates annual stroke/thromboembolism risk in non-valvular atrial fibrillation to guide anticoagulation decisions.

HAS-BLED

Estimates major bleeding risk in patients with atrial fibrillation considered for anticoagulation, highlighting modifiable risk factors.