Table 3.

Characteristics of included RCT

Reference	Type of study	Aim	Treatment	Sample size and amount of older participants	Follow-up	Outcomes
Britton 1987 [58]	RCT	To study the effectiveness of high-dose ASA after cerebral infarction	ASA 1.5 g/d vs placebo	N = 505, mean age 68 years	2 years	Primary outcomes: Recurrent stroke or death. Secondary outcomes: myocardial infarction, TIA
Diener 2004 [53]	RCT	To assess whether addition of ASA to clopidogrel could have a greater benefit than clopidogrel alone in prevention of vascular events with potentially higher bleeding risk	ASA 75 mg/d + clopidogrel 75 mg/d vs placebo + clopidogrel 75 mg/d	N = 7599, placebo + clopidogrel: mean age 66.1 years, 54% older than 65 years. ASA + clopidogrel: mean age 66.5 years, 56% older than 65 years. Subgroup analysis age ≥ 65 years	18 months	Primary outcomes: composite of ischaemic stroke, myocardial infarction, vascular death or rehospitalisation for an acute ischaemic event. Secondary outcomes: Individual and various combinations of each of the outcomes forming the primary endpoint, any death, any stroke
EAFT 1993 [34]	RCT	To assess the preventive benefit of anticoagulation or ASA in patients with recent transient ischaemic attack or minor ischaemic stroke	ASA 300 mg/d vs OAC INR 2.5–4.0 vs placebo	N = 1007, OAC: mean age 71 years. 80% older than 65 years. ASA: mean age 73 years, 84% older than 65 years. Placebo: mean age 73 years, 84% older than 65 years	2.3 years	Primary outcomes: death from vascular disease, non-fatal stroke (including haemorrhage), non-fatal myocardial infarction or systemic embolism. Secondary outcomes: death from all causes, all strokes, major thromboembolic events
Huynh 2001 [36]	RCT	To test the hypothesis that moderate-intensity warfarin either alone or in combination with low-dose ASA will be more effective than ASA alone for the secondary prevention of coronary events in patients with previous CABG	ASA 80 mg/d + placebo, warfarin INR 2–2.5 + placebo, ASA 80 mg/d + warfarin INR 2–2.5	N = 135, ASA + placebo: mean age 68, 61% older than 65 warfarin + placebo: mean age 67, 57% older than 65, ASA + warfarin: mean age 66, 53% older than 65 years. Subgroup analysis age ≥ 65 years	12 months	Primary outcomes: composite end point of any-cause death, myocardial infarction, unstable angina requiring a new hospitalization. Secondary outcome: performance of reperfusion procedure (either percutaneous or open chest)
Ikeda 2014 [35]	RCT	To determine whether daily low-dose ASA reduces the incidence of cardiovascular events in older Japanese patients with multiple atherosclerotic risk factors	ASA 100 mg/d vs control	N = 14,464, ASA: mean age 70.6, 82% older than 65. Control: mean age 70.5, 81% older than 65	5.02 years	Primary outcome: composite of death from cardiovascular causes, non-fatal stroke and non-fatal myocardial infarction. Secondary outcomes: composite of primary outcomes + TIA, angina pectoris and arteriosclerotic disease requiring surgery or intervention; death from cardiovascular causes, non-fatal stroke, non-fatal myocardial infarction, TIA, angina pectoris, arteriosclerotic disease requiring surgery or intervention, serious extracranial haemorrhage
Kjeldsen 2000 (HOT) [31]	RCT	To study the relationship between three levels of target diastolic blood pressure and cardiovascular events in hypertensive patients and to examine the effects of 75 mg ASA daily versus placebo	ASA 75 mg/d	N = 18,790; men: mean age 60.8 years, 28% older than 65 years. Women: mean age 62.3 years, 36% older than 65 years. Subgroup analysis age ≥ 65 years	3.8 years	Major CV events, MI, Stroke CV mortality, total mortality
Liu 2014 [47]	RCT	To compare the therapeutic warfarin and ASA efficacies for treatments of atrial fibrillation complicated with stable coronary heart disease	Warfarin INR 1.6–2.5, ASA 100 mg/d	N = 101, warfarin: mean age 84.8 years, ASA: mean age 84.4 years. 100% older than 65 years	2 years	Primary outcome: ischaemic stroke, systemic embolism. Secondary outcomes: non-fatal myocardial infarction and all causes of death
Ogawa 2008 [33]	RCT	To examine the efficacy of low-dose ASA for the primary prevention of atherosclerotic events in patients with type 2 diabetes	ASA 81–100 mg/d vs control	N = 2539, mean age 65 years. ASA: 50% older than 65 years. Non-ASA group: 46% older than 65 years. Subgroup analysis age ≥ 65 years	4.37 years	Primary outcomes: Any atherosclerotic event (composite endpoint of sudden death, death from coronary, cerebrovascular, and aortic causes, non-fatal acute myocardial infarction, unstable angina, newly developed exertional angina, non-fatal ischaemic and haemorrhagic stroke, transient ischaemic attack, non-fatal aortic and peripheral vascular disease). Secondary outcomes: each primary endpoint and combinations of primary endpoints, death from any cause
Silagy 1993 [32]	RCT	To investigate the incidence of adverse effects resulting from the use of regular low-dose ASA in an otherwise healthy elderly population	ASA 100 mg/d vs placebo	N = 400, mean age 73 years, 100% older than 65 years	12 months	Adverse events (gastrointestinal symptoms, gastrointestinal bleeding, easy bruising, nose bleeds), haematologic parameters
Uchiyama 2016 [50]	RCT	To evaluate the effect of ASA on the risk of stroke and intracranial haemorrhage in the Japanese Primary Prevention Project.	ASA 100 mg/d vs control	N = 14,464, ASA: mean age 70.6 years, 82% older than 65 years. No ASA: 70.5 years, 81% older than 65 years	5.02 years	Primary outcomes: composite of death from cardiovascular causes (including fatal myocardial infarction, fatal stroke, and other cardiovascular death), non-fatal stroke and non-fatal MI. Secondary outcomes: composite of the same events as the primary end points plus TIA, angina pectoris and atherosclerotic disease requiring surgery or intervention. Death from cardiovascular disease, death from nonvascular causes, non-fatal stroke, non-fatal MI, TIA, angina pectoris, atherosclerotic disease requiring surgery or intervention, serious extracranial haemorrhage requiring transfusion or hospitalization.
Wiviott 2007 [51]	RCT	To compare prasugrel with clopidogrel for the prevention of thrombotic complications in patients with an acute coronary syndrom and scheduled percutaneous coronary intervention	Prasugrel 60 mg loading-dose, 10 mg daily maintenance dose vs clopidogrel 300 mg loading-dose, 75 mg daily maintenance	N = 13,608, mean age 61 years. Subgroup analysis age ≥ 65 years.	6–15 months	Primary outcomes: composite of death from cardiovascular causes, non-fatal myocardial infarction, or non-fatal stroke. Secondary outcomes: stent thrombosis and a composite of death from cardiovascular causes, non-fatal myocardial infarction, non-fatal stroke, or rehospitalisation due to a cardiac ischaemic event. Safety outcomes: major bleeding not related to coronary-artery bypass grafting, life threatening bleeding not related to coronary-artery bypass grafting, major and minor bleeding

ASA acetylsalicylic acid, BID twice a day, CABG coronary artery bypass graft, CV cardiovascular, INR international normalized ratio, MI myocardial infarction, OAC oral anticoagulation, RCT randomised controlled trial, TIA transient ischemic attack