Table 1. Aspirin dose and participant characteristics in the 9 RCTs of primary prevention.
| Study Year published | Aspirin dose mg* | Control arm | Gender% male | Design | Current smoker % | Additional therapies | Participants |
|---|---|---|---|---|---|---|---|
| BDT 1988 [2] | 300 or 500 | No placebo | 100 | Open label | 31 | None | n = 5,139 |
| PHS 1989 [8] | 325 eod | Placebo | 100 | Double blind | 11 | Beta-carotene | n = 22,071 |
| HOT 1998 [5] | 75 | Placebo | 53 | Double blind | 16 | Various** | n = 18,790 |
| TPT 1998 [6] | 75 | Placebo | 100 | Double blind | 41 | Warfarin | n = 5,058 |
| PPP 2001 [7] | 100 | No Placebo | 42 | Open label | 15 | Vitamin E | n = 4,495 |
| WHS 2005 [9] | 100 eod | Placebo | 0 | Double blind | 10.1 | Vitamin E | n = 39,876 |
| Beta-carotene | |||||||
| POPADAD 2008 [3] | 100 | Placebo | 44 | Double blind | 32 | Antioxidant | n = 1,276 |
| JPAD 2008 [4] | 81 or 100 | No placebo | 55 | Open label | 4.4 | None | n = 2,539 |
| AAA 2010 [10] | 100 | Placebo | 28 | Double blind | 33 | None | n = 3,350 |
BDT=British Doctors Trial (BMJ 296,313); PHS=Physician’s Health Study (NEJM 321, 129); HOT=Hypertension Optimal Treatment (Lancet 351, 1755); TPT=Thrombosis Prevention Trial (Lancet 351, 233); PPP=Primary Prevention Project (Lancet 357, 89); WHS=Women’s Health Study (NEJM 352, 1293); POPADAD=Prevention Of Progression of Arterial Disease And Diabetes (BMJ 337, a1840); JPAD=Japanese Primary Prevention of Atherosclerosis with Aspirin for Diabetes (JAMA 300, 2134); AAA=Aspirin for Asymptomatic Atherosclerosis (JAMA 303, 841)
* aspirin taken each day unless specified; eod = every other day; ** therapies to achieve a target blood pressure