A Practical Guide to Haemostasis

The ORBIT-AF Bleeding Score


The ORBIT-AF Bleeding Score [Outcomes Registry for Better Informed Treatment of Atrial Fibrillation] is used to assess the risk of bleeding in patients with Atrial Fibrillation [AF] on anticoagulation with oral anticoagulants.

Major bleeding was defined as:
i. Fatal bleeding
ii. Symptomatic bleeding in a critical area or organ (intra-cranial, intra-spinal, intra-ocular, retroperitoneal, intra-articular or pericardial, or intramuscular with compartment syndrome),
iii. Bleeding causing a fall in haemoglobin of ≥20 g/L [≥2 g/dL] or leading to the transfusion of two or more units of whole blood or red cells.

In the original study, 93.4% of patients were treated with Warfarin and 6.6% with Dabigatran. The algorithm was also used to study the risk of bleeding in the ROCKET-AF study [- Rivaroxaban Once-daily oral direct factor Xa inhibition compared with vitamin K antagonism for prevention of stroke and embolism trial in atrial fibrillation]. 

The ORBIT-AF Bleeding Score:

Select Criteria:

[O] Older Age:  ≥75 years old
1 Point
[R] Reduced Haemoglobin/Reduced Haematocrit/Anaemia

|Hb <130 g/L Male; Hb <120 g/L Females
Hct: <40% Males; <30% Females

History of anaemia
2 Points
[B] Bleeding History
2 Points
[I] Insufficient renal function. eGFR <60mg/dL
1 Point
[T] Treatment with Anti-platelet agents
1 Point


Maximum Score 7 points

Score Bleeds per 100 patient years Bleed Risk Category
0 1.7 Low
1 2.3
2 2.9
3 4.7 Medium
4 6.8 High
5 9.0
6 12.3
7 14.9

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