Table 1. Characteristics of included trials of aspirin for primary cardiovascular prevention.

Study, year	Country	Study design	Randomly, N	Dose	Inclusion	Male%	Follow-up, years	Quality
PHS, 1989 (2)	United States	2×2 RCT, beta carotene	22,071	325 mg alternate day	Male physicians aged 40–84 y	100	5.0	High
HOT, 1998 (1)	26 countries	3×2 RCT, felodipine + other agents to achieve target blood pressure	18,790	75 mg/d	Aged 50–80 y with hypertension	53	3.8	High
TPT, 1998 (17)	United Kingdom	2×2 RCT, warfarin	2,540	75 mg/d	Men with high IHD risk aged 45–69 y	100	6.8	High
WHS, 2005 (16)	United States	2×2 RCT, vitamin E	39,876	100 mg alternate day	Healthy women 45 y of age or older	0	10.1	High
POPADAD, 2008 (4)	Scotland	2×2 RCT, antioxidant capsule	1,276	100 mg/d	Aged 40 y or more with DM and ABI ≤0.99	44.1	6.7	High
AAA, 2010 (3)	Scotland	RCT	3,350	100 mg/d	ABI ≤0.95 aged 50–75 y	28.5	8.2	High
ASPREE, 2018 (6)	Australia and United States	RCT	19,114	100 mg/d	70 years of age or older (or ≥65 years of age among blacks and Hispanics in the United States)	43.6	4.7	High
ASCEND, 2018 (7)	United Kingdom	RCT	15,480	100 mg/d	DM at least 40 y of age	62.6	7.4	High
ARRIVE, 2018 (5)	7 countries	RCT	12,546	100 mg/d	Aged ≥55 y (male) or 60 y (female) with an average cardiovascular risk	70.4	5.0	High

PHS, Physicians’ Health Study; HOT, Hypertension Optimal Treatment; TPT, Thrombosis prevention Trial; WHS, Women’s Health Study; POPADAD, Prevention Of Progression of Arterial Disease And Diabetes; AAA, Aspirin for Asymptomatic Atherosclerosis; ASPREE, Aspirin in Reducing Events in the Elderly; ASCEND, A Study of Cardiovascular Events In Diabetes; ARRIVE, Aspirin to Reduce Risk of Initial Vascular Events; RCT, randomized controlled trial; IHD, ischemic heart disease; DM, diabetes mellitus; ABI, ankle brachial index.