Can aspirin be given to patients with hypertension and type 2 diabetes for primary prevention of cardiovascular events?

Aspirin Use in Patients with Hypertension and Type 2 Diabetes for Primary Prevention

Low-dose aspirin (75-162 mg/day) should be considered for primary prevention in patients with hypertension and type 2 diabetes who are aged ≥50 years with at least one additional major cardiovascular risk factor and no increased bleeding risk. 1, 2

Patient Selection for Aspirin Therapy

• Aspirin therapy (75-162 mg/day) is recommended for primary prevention in diabetic patients aged ≥50 years who have at least one additional major cardiovascular risk factor (family history of premature atherosclerotic cardiovascular disease, hypertension, dyslipidemia, smoking, or albuminuria) 1, 2
• Patients with hypertension and diabetes have a two- to fourfold increased risk of dying from cardiovascular disease complications, making them potential candidates for preventive aspirin therapy 1
• Aspirin therapy is most beneficial in patients whose 10-year cardiovascular risk is >10%, where benefits are likely to outweigh bleeding risks 2
• For patients with controlled hypertension (<150/90 mmHg) and evidence of target organ damage, low-dose aspirin provides greater benefit 2

Evidence Supporting Aspirin Use

• The Hypertension Optimal Treatment (HOT) Trial showed that aspirin (75 mg/day) significantly reduced cardiovascular events by 15% and myocardial infarction by 36% in hypertensive patients 1
• In the U.S. Physicians' Health Study, diabetic men taking aspirin (325 mg every other day) had a 61% relative risk reduction in myocardial infarction compared to placebo 1
• The Early Treatment Diabetic Retinopathy Study (ETDRS) demonstrated that aspirin therapy significantly lowered the relative risk for myocardial infarction to 0.72 (CI 0.55-0.95) 1

Evidence Against Aspirin Use

• Recent meta-analyses have found no statistically significant reduction in the risk of major cardiovascular events or all-cause mortality when aspirin was compared with placebo in people with diabetes and no pre-existing cardiovascular disease 1
• The JPAD trial (10-year follow-up) showed that low-dose aspirin did not reduce cardiovascular events in patients with type 2 diabetes in a primary prevention setting 3
• Some observational studies have even suggested a paradoxical increase in cardiovascular risk with aspirin use in primary prevention for diabetic patients 4

Bleeding Risk Considerations

• Aspirin increases the relative risk of major gastrointestinal bleeding (relative risk 1.6), even with relatively low doses 1
• Estimated rates of major gastrointestinal bleeding are approximately 2-4 per 1,000 middle-aged persons (4-12 per 1,000 for older persons) given aspirin for 5 years 1
• Aspirin may increase rates of hemorrhagic strokes by 0-2 per 1,000 persons over 5 years 1
• Contraindications to aspirin therapy include allergy, bleeding tendency, anticoagulant therapy, recent gastrointestinal bleeding, and clinically active hepatic disease 1

Dosing Recommendations

• The optimal dose for primary prevention is 75-100 mg daily 2
• Enteric coating does not appear to reduce bleeding risk 1
• For patients with diabetes, some evidence suggests that twice-daily dosing may be more effective due to faster platelet turnover in diabetic patients 5

Algorithm for Decision Making

1. Assess cardiovascular risk factors:

   • Age ≥50 years 1, 2
   • Presence of additional risk factors (hypertension, dyslipidemia, smoking, family history, albuminuria) 1
   • Calculate 10-year cardiovascular risk (aim for >10% to justify aspirin use) 2

2. Evaluate bleeding risk:

   • Check for history of GI bleeding, peptic ulcer disease 1
   • Assess for concurrent use of anticoagulants or NSAIDs 2
   • Consider age (higher bleeding risk in those >70 years) 2

3. Prescribe aspirin if:

   • Patient has multiple cardiovascular risk factors 1
   • 10-year cardiovascular risk >10% 2
   • No contraindications or high bleeding risk 1
   • Blood pressure is well-controlled (<150/90 mmHg) 2

4. Monitor for:

   • GI symptoms suggesting bleeding 1
   • Signs of hemorrhagic stroke 1
   • Blood pressure control 2

Special Considerations

• Aspirin is not recommended for patients aged <21 years due to risk of Reye syndrome 2
• For patients aged >70 years without established cardiovascular disease, the balance appears to have greater risk than benefit 2
• Aspirin therapy should be avoided in patients with uncontrolled hypertension due to increased bleeding risk 1
• Aspirin does not appear to increase risk for retinal or vitreous hemorrhage in diabetic patients with retinopathy 1