What are the guidelines for using aspirin (acetylsalicylic acid) for primary prevention of cardiovascular events?

Guidelines for Aspirin Use in Primary Prevention of Cardiovascular Events

Aspirin should not be routinely used for primary prevention of cardiovascular disease as the risks of bleeding often outweigh the benefits for most individuals, especially those over 60 years of age. 1

Patient Selection Algorithm

Recommended for Consideration:

• Ages 40-59 years with:
  • 10-year cardiovascular risk ≥10%
  • Low bleeding risk
  • Individual decision-making required 1

Not Recommended:

• Ages ≥60 years (regardless of risk factors) 1
• Patients with high bleeding risk:
  • History of GI bleeding/ulcers
  • Concurrent anticoagulants or NSAIDs
  • Uncontrolled hypertension 2
  • Age <21 years (risk of Reye syndrome) 3

Risk Assessment

Cardiovascular Risk Factors to Consider:

• Family history of premature CVD
• Hypertension
• Dyslipidemia
• Smoking
• Diabetes mellitus
• Chronic kidney disease/albuminuria 2

Bleeding Risk Factors:

• Age >70 years
• History of GI bleeding or ulcers
• Concurrent use of anticoagulants or NSAIDs
• Uncontrolled hypertension 2

Dosage Recommendations

• For eligible patients: 75-162 mg daily 3, 2
• In the US, most common low-dose tablet is 81 mg 3

Special Populations

Diabetes Patients:

• Consider aspirin for primary prevention in diabetic patients aged 50-69 years with at least one additional cardiovascular risk factor and low bleeding risk 3, 2
• Not recommended for diabetic patients <50 years with no additional risk factors 2
• Meta-analysis suggests aspirin has no effect on nonfatal MI or cardiovascular death in diabetics but increases bleeding risk by 49% 4

Benefits vs. Harms

Benefits:

• Reduces risk of coronary heart disease by 28% 3
• Reduces risk of nonfatal myocardial infarction by 21% in healthy individuals 4
• No significant effect on total mortality or stroke 3

Harms:

• Increases major bleeding risk by 48% 4
• Estimated rates of major GI bleeding: 2-4 per 1,000 middle-aged individuals and 4-12 per 1,000 older individuals given aspirin for 5 years 3
• Small increase in hemorrhagic stroke risk (0-2 per 1,000 persons given aspirin for 5 years) 3

Current Guideline Positions

The 2022 US Preventive Services Task Force recommends:

• Ages 40-59 years with ≥10% 10-year CVD risk: individual decision (C recommendation)
• Ages ≥60 years: against initiating aspirin (D recommendation) 1

The American Diabetes Association suggests:

• Low-dose aspirin for primary prevention in patients with diabetes who have increased CVD risk (>10% 10-year risk)
• Not recommended for men <50 years or most women <60 years with low CVD risk 3

The American Heart Association and American Stroke Association:

• Consider aspirin when 10-year CVD risk is 6-10% and benefits outweigh risks 3

Clinical Pitfalls to Avoid

1. Overestimating benefit: Recent evidence shows aspirin's benefit in primary prevention is small and often outweighed by bleeding risk 5

2. Neglecting bleeding risk assessment: Always evaluate bleeding risk before recommending aspirin 2

3. Inappropriate discontinuation: If a patient already has established CVD (secondary prevention), aspirin should not be discontinued as benefits clearly outweigh risks 2

4. Medication interactions: Ibuprofen may block aspirin's cardioprotective effects when taken together 2

5. Overlooking age considerations: Aspirin is not recommended for primary prevention in those ≥60 years regardless of risk factors 1