What are the guidelines for using Aspirin (Acetylsalicylic Acid) in adults over 40 with a history of cardiovascular disease or at high risk of developing it, including those with hypertension, hyperlipidemia, or diabetes?

Aspirin Use Guidelines for Cardiovascular Disease Prevention

Secondary Prevention (Established CVD)

For adults with a history of cardiovascular disease (myocardial infarction, stroke, or atherosclerotic cardiovascular disease), aspirin 75-162 mg daily is strongly recommended and should be continued indefinitely. 1, 2, 3

• The most common formulation in the U.S. is 81 mg daily, which provides equivalent cardiovascular protection to higher doses while minimizing bleeding complications 1, 2, 3
• This recommendation applies to all adults with documented ASCVD, regardless of age, as the benefits far outweigh bleeding risks in this population 1, 3
• For patients with documented aspirin allergy, clopidogrel 75 mg daily should be substituted 1, 3

Primary Prevention (No Prior CVD Events)

Age 40-59 Years with High Risk

Aspirin 75-162 mg daily may be initiated for primary prevention in adults aged 40-59 years with a 10-year cardiovascular disease risk ≥10% who are not at increased bleeding risk. 2, 4

• For patients with diabetes aged ≥50 years plus at least one additional major risk factor (hypertension, dyslipidemia, smoking, family history of premature ASCVD, or chronic kidney disease/albuminuria), aspirin 75-162 mg daily is reasonable 1, 2, 3
• The net benefit is small in this age group, with approximately equal numbers of cardiovascular events prevented and bleeding episodes induced 1, 4
• Use 75-81 mg daily as the lowest effective dose to minimize gastrointestinal bleeding while maintaining efficacy 1, 2, 3

Age ≥60 Years

Aspirin should NOT be initiated for primary prevention in adults aged 60 years or older, as bleeding risks outweigh cardiovascular benefits in this population. 2, 4

• For patients over age 70 years without established cardiovascular disease, the balance clearly favors greater risk than benefit 1, 3
• Major bleeding risk increases substantially with age, occurring at approximately 5 per 1,000 patients per year in real-world settings 3

Low-Risk Patients

Aspirin is not recommended for primary prevention in adults with low cardiovascular risk (<10% 10-year risk), regardless of age. 3, 4

• For patients aged <50 years with diabetes and no other major ASCVD risk factors, bleeding risks outweigh minimal cardiovascular benefits 1, 3

Contraindications and High Bleeding Risk

Do not prescribe aspirin in patients with:

• Active bleeding or recent gastrointestinal bleeding 1, 3
• Known aspirin allergy or bleeding disorders 1, 3
• Concurrent anticoagulation therapy 1, 3
• Uncontrolled hypertension (increases bleeding risk substantially) 3
• Age <21 years (risk of Reye syndrome) 3
• History of gastrointestinal ulcers, anemia, or chronic kidney disease (relative contraindications requiring careful risk-benefit assessment) 1, 2
• Concurrent use of NSAIDs or corticosteroids (significantly increases bleeding risk) 2, 3

Dosing Recommendations

The optimal aspirin dose for both primary and secondary prevention is 75-162 mg daily, with 75-81 mg being preferred. 1, 2, 3

• The ADAPTABLE trial demonstrated no significant differences in cardiovascular events or major bleeding between 81 mg and 325 mg daily doses in patients with established cardiovascular disease 1, 2
• Higher doses (>162 mg) do not provide additional cardiovascular benefit but significantly increase bleeding risk 2, 5
• Major bleeding risk with aspirin is approximately 2-5 per 1,000 patients per year, with gastrointestinal bleeding being the most common adverse effect 1, 2, 3

Special Populations

Diabetes with Hypertension

For patients with both diabetes and hypertension aged ≥50 years with controlled blood pressure and at least one additional cardiovascular risk factor, aspirin 75-162 mg daily may be considered if bleeding risk is low. 3

• Blood pressure must be controlled (<150/90 mmHg) before initiating aspirin to minimize bleeding risk 3
• The HOT trial demonstrated that aspirin 75 mg daily reduced cardiovascular events by 15% and myocardial infarction by 36% in well-controlled hypertensive patients with diabetes, though major bleeds were twice as common 3

Women-Specific Considerations

Aspirin reduces myocardial infarction risk in men but not women, while reducing stroke risk in women but not men in primary prevention. 1, 3

• For women ≥65 years with controlled blood pressure and high cardiovascular risk (>6-10% 10-year risk), aspirin 81 mg daily or 100 mg every other day may be considered 3
• Elderly women face substantially higher bleeding risk that must be carefully weighed against cardiovascular benefits 3

Common Pitfalls to Avoid

• Do not use aspirin doses >162 mg daily – higher doses increase bleeding without improving cardiovascular protection 1, 2, 5
• Do not initiate aspirin in patients ≥60 years for primary prevention – this is now explicitly recommended against by current guidelines 2, 4
• Do not prescribe aspirin without assessing bleeding risk factors – age >70 years, history of GI bleeding, anemia, renal disease, and concurrent medications significantly increase bleeding risk 1, 2, 3
• Do not assume aspirin is appropriate for all diabetic patients – only those aged ≥50 years with additional risk factors and low bleeding risk should be considered 1, 2, 3