- Aspirin protects against atherothrombosis while increasing the risk of major bleeding.
- Current Studies
- The ARRIVE study
- Daily low dose aspirin (100 mg) did not reduce the long-term risk for cardiovascular or cerebrovascular events in more than 12,000 adults aged ≥ 55 years considered to be at a moderate risk of CVD.
- stroke incidence did not differ significantly between treatment and placebo groups,
- rates of gastrointestinal bleeding and other minor bleeding were increased with aspirin.
- The ASPREE study
- low dose aspirin for primary prevention in 19,114 patients aged ≥ 70 years also did not reduce rates of all cardiovascular events, while significantly increasing the risk of major haemorrhage
- The ARRIVE study
NOTE: Diabetes mellitus is associated with a substantially increased CVD risk, meaning patients are generally excluded from primary prevention trials.
- the ASCEND study
- over 15,000 adults aged ≥ 40 years with any type of diabetes and no prior history of cardiovascular events were randomly assigned low dose aspirin or placebo.
- Aspirin reduced serious cardiovascular events by 12% (8.5% versus 9.6%; p=0.01),
- Major bleeding events increased by 29% (3.2% versus 4.1%; p=0.003)
- Absolute benefits were outweighed by the added risk of bleeding in patients with diabetes.
In Australia
- Currently no guidelines recommended in Australian guidelines
- clinical judgement is recommended in making decisions for aspirin use
- Further trials are currently underway to more comprehensively understand the risks and benefits of aspirin in primary CVD and cancer prevention
In USA
- The US Preventive Services Task Force makes a level IB recommendation for the use of aspirin in people
- aged 50–59 years + moderate to high CVD risk
- for the primary prevention of CVD and colon cancer
- if there is no increased risk of bleeding.
New Zealand:
- Aspirin is not recommended in people aged ≥ 70 years without a history of CVD
- as the risk of major haemorrhage outweighs any potential benefits in this age group
- Consider the use of aspirin for primary prevention in people
- aged < 70 years
- ≥ 15% five-year CVD risk
- The benefits of aspirin may outweigh the increased risk of bleeding for primary CVD prevention in patients aged under 70 years with a ≥ 15% five-year CVD risk
- potential benefit (reduction in non-fatal myocardial infarction and possible small net years gained) and bleeding risk must be carefully assessed and discussed during shared decision-making
- existing disease (secondary prevention)
- existing CVD/documented coronary disease
- carotid disease (plaque on ultrasound)
- high coronary calcium score on CT scan (> 400)
considered to equate to high risk (>15%) and aspirin is recommended.
| Age | Five-year CVD risk level | Recommendation for primary prevention of CVD | Recommendation for secondary prevention of CVD | |
| New CVD risk level (based on NZ Primary Prev eqn) | Old CVD risk level (based on Framingham eqns) | |||
| < 70 years | < 5% | < 10% | Aspirin is not recommended Intervention with lipid-lowering or blood pressure-lowering medicines has little benefit | Aspirin is recommended† **Provide lifestyle advice and pharmacotherapy for modifiable risk factors |
| 5–15% | 10–20% | Aspirin is not recommended Discuss the benefits of lipid-lowering or blood pressure-lowering medicines | ||
| ≥ 15% | ≥ 20% | Consider aspirin Lipid-lowering or blood pressure-lowering medicines are strongly recommended | ||
| ≥ 70 years | All levels | All levels | Aspirin is not recommended | |
| Asymptomatic carotid disease Asymptomatic coronary disease or plaque | Consider aspirin Lipid-lowering or blood pressure-lowering medicines are strongly recommended | |||
Aspirin contraindications
- Active peptic ulceration, uncontrolled blood pressure and other major bleeding risks (including most people receiving an anticoagulant)
- Aspirin hypersensitivity/intolerance
- Severe hepatic or renal impairment
- all patients older than 70 years should not receive aspirin if they do not have a history of CVD, meaning de-prescribing should be considered. This recommendation is reinforced by the recent ASPREE study