Should I take aspirin (acetylsalicylic acid) for cardiovascular risk reduction?

Aspirin for Cardiovascular Risk Reduction

For most individuals without established cardiovascular disease, low-dose aspirin is generally not recommended for primary prevention due to the minimal cardiovascular benefits being offset by increased bleeding risks. 1

Decision Algorithm for Aspirin Use

For Secondary Prevention (Established CVD)

• Strongly recommended: Use aspirin 75-162 mg daily for all patients with:
  • History of myocardial infarction
  • History of stroke
  • Documented atherosclerotic cardiovascular disease (ASCVD)
  • Peripheral arterial disease

For Primary Prevention (No Established CVD)

1. Age < 40 years: Not recommended regardless of risk factors
2. Age 40-59 years:
   • With ≥10% 10-year ASCVD risk AND low bleeding risk: Consider aspirin 81 mg daily 2
   • With diabetes AND at least one additional risk factor: Consider aspirin if low bleeding risk 1
   • Without additional risk factors: Not recommended
3. Age 50-69 years:
   • With diabetes AND at least one additional risk factor: Consider aspirin if low bleeding risk 1
   • Without additional risk factors: Not recommended
4. Age ≥ 70 years: Not recommended regardless of risk factors 1

Risk Assessment

ASCVD Risk Factors to Consider

• Diabetes
• Hypertension
• Dyslipidemia
• Smoking
• Family history of premature ASCVD
• Chronic kidney disease/albuminuria

Bleeding Risk Factors (Contraindications)

• History of gastrointestinal bleeding or peptic ulcer disease
• Concurrent use of other anticoagulants or NSAIDs
• Age > 70 years
• Thrombocytopenia or coagulopathy
• Severe liver disease
• Uncontrolled hypertension
• History of hemorrhagic stroke

Evidence Analysis

The 2020 American Diabetes Association guidelines provide the most recent comprehensive recommendations on aspirin use. They highlight that aspirin has only a modest effect on ischemic vascular events, with the absolute decrease in events depending on underlying ASCVD risk 1. The ASCEND trial showed a 12% reduction in cardiovascular events but also a significant 29% increase in major bleeding 1.

For every 1,000 patients taking aspirin for primary prevention, approximately 2-4 middle-aged persons (or 4-12 older persons) will experience major gastrointestinal bleeding over 5 years 1. Additionally, aspirin may increase hemorrhagic stroke risk by 0-2 per 1,000 persons over 5 years 1.

The 2022 US Preventive Services Task Force recommendation statement concluded that aspirin use for primary prevention in adults aged 40-59 years with ≥10% 10-year CVD risk has only a small net benefit, while initiating aspirin in adults 60 years or older has no net benefit 2.

Dosing Considerations

If aspirin is indicated:

• Use the lowest effective dose (typically 81 mg daily in the US)
• No evidence supports higher doses providing additional cardiovascular benefit
• Higher doses increase bleeding risk 1, 3

Common Pitfalls to Avoid

1. Automatic prescribing: Don't prescribe aspirin for primary prevention without assessing both cardiovascular and bleeding risks
2. Ignoring age: Patients >70 years have significantly higher bleeding risks that typically outweigh benefits
3. Overlooking interactions: NSAIDs can interfere with aspirin's cardioprotective effects and increase bleeding risk 4
4. Failing to reassess: Cardiovascular and bleeding risks change over time and require periodic reevaluation
5. Neglecting shared decision-making: The modest benefits versus risks should be discussed with patients, especially in primary prevention scenarios

Remember that aspirin resistance occurs in some patients, but routine platelet function testing is not currently recommended in clinical practice 5.