Table 3.

Studies of intensity of oral anticoagulation treatment in patients with antiphospholipid syndrome and previous arterial thrombosis

Reference	Design	Comparison	Percentage with arterial thrombosis history	Intervention	Control	Number of patient-years, intervention	Number of patient-years, control	Events, intervention	Events, control	Relative effect (95% CI)	Study quality
Recurrent thrombosis
Crowther et al 200325	RCT	Direct	100	Warfarin INR 3–4	Warfarin INR 2–3	35 py	38 py	8.6/100 py	2.6/100 py	HR 3.1 (0.3 to 30.0)	Low risk of bias*
Finazzi et al 200526	RCT	Indirect	32	Warfarin INR 3–4.5	Warfarin INR 2–3	189 py	181 py	3.1/100 py	1.6/100 py	–	High risk of bias*
Rosove and Brewer 199227	Retrospective cohort	Indirect	44	Warfarin INR 3–4	Warfarin INR 2–3	110.2 py	40.9 py	0	7/100 py	–	Intermediate quality
Khamashta et al 199528	Retrospective cohort	Indirect	46	Warfarin ≥INR 3.0	Warfarin INR <3.0	197.3 py	141.3 py	1.5/100 py	23/100 py	–	High quality
Total		Direct and indirect								RR 0.46 (0.06 to 3.52) I2=83%
Major bleeding
Crowther et al 200325	RCT	Direct	100	Warfarin INR 3–4	Warfarin INR 2–3	111 py	133 py	2.7/100 py	3.0/100 py	HR 1.0 (0.02 to 4.8)	Low risk of bias*
Finazzi et al 200526	RCT	Indirect	32	Warfarin INR 3–4.5	Warfarin INR 2–3	189 py	181 py	1.0/100 py	1.6/100 py	–	High risk of bias*
Khamashta et al 199528	Retrospective cohort	Indirect	46	Warfarin ≥3.0	Warfarin <3.0	197.3 py	141.3 py	1.7/100 py	0	–	High quality
Total		Direct and indirect								RR 0.86 (0.28 to 2.67) I2=0%

*Risk of bias for randomised controlled trials using the Cochrane tool.

INR, international normalised ratio; RCT, randomised controlled trial; py, patient-years.