Table 8.

 Summary of ‘anaemia’ as a risk factor for bleeding in AF patients receiving OACs

Study	Subjects (n)	Type of OACs	Definition	Main findings	HR (95% CI)	P value
Fang et al., 2011	9186	VKA	Hb <13 g/dL in men and <12 g/dL in women	The rate of major haemorrhage was 12.1% in patients without anaemia vs. 18.8% in those with anaemia.	HR 4.2 (3.4–5.3)	<0.001
O'Brien et al., 2015	7411	VKA Dabigatran	Reduced Hb/haematocrit/history of anaemia	Reduced haemoglobin/haematocrit/history of anaemia had good ability to identify those who bled vs. not.	HR 2.07 (1.74–2.47)	NR
Bonde et al., 2019	18 734	VKA Dabigatran Rivaroxaban	(1) No anaemia (Hb >7.45 mmol/L for women and >8.07 mmol/L for men) (2) Mild anaemia (Hb 6.83–7.45 mmol/L for women and 6.83–8.07 mmol/L for men) (3) Moderate/severe anaemia (Hb <6.83 mmol/L for women and men).	OAC was associated with a 5.3% (95% CI 2.1–8.7%) increased standardized absolute risk of major bleeding among AF patients with moderate/severe anaemia.	HR 1.78 (1.30–2.48)	NR
Krittayaphong et al., 2021	1562	VKA NOACs	Hb <13 g/dL for male and <12 g/dL for female	Anaemia was found to be an independent risk factor for major bleeding.	HR 2.96 (1.81–4.84)	NR

AF, atrial fibrillation; Hb, haemoglobin; HR, hazard ratio; NR, not reported; OACs, oral anticoagulants; NOAC, non-vitamin K antagonist oral anticoagulant; VKA, vitamin K antagonists.