ORBIT total score = sum of points for five predictors (0–7 points).

Component	Definition	Points
Older age	Age ≥75 years	1
Reduced haemoglobin / haematocrit / anaemia	Haemoglobin <130 g/L (men) or <120 g/L (women), haematocrit <0.40 (men) or <0.36 (women), or documented history of anaemia	2
Bleeding history	Any prior gastrointestinal bleed, intracranial haemorrhage, or haemorrhagic stroke	2
Insufficient kidney function	eGFR <60 mL/min/1.73 m²	1
Antiplatelet treatment	Current treatment with an antiplatelet agent	1

Risk categories (major bleeding in the derivation cohort):

Total score	Risk category	Major bleeds per 100 patient-years (approx.)
0–2	Low	≈2.4
3	Medium	≈4.7
4–7	High	≈8.1

ORBIT Bleeding Risk Score for Atrial Fibrillation