E) Its administration at a dose of 75–100 mg daily is recommended for primary prevention in individuals at moderate cardiovascular risk
The statement about aspirin being recommended at 75-100 mg daily for primary prevention in moderate cardiovascular risk individuals is FALSE and represents outdated guidance that has been superseded by more recent evidence.
Why This Statement is Incorrect
The most recent and highest-quality guideline evidence demonstrates a fundamental shift away from routine aspirin use in primary prevention for moderate-risk individuals:
The 2019 ACC/AHA Primary Prevention Guidelines 1 explicitly downgraded aspirin recommendations, stating that low-dose aspirin (75-100 mg daily) receives only a Class IIb recommendation (meaning it "might be considered") for select adults 40-70 years of age at higher ASCVD risk but NOT at increased bleeding risk. More importantly, it carries a Class III: Harm recommendation for adults >70 years of age, meaning it should NOT be administered routinely.
The 2016 USPSTF guidelines 2 similarly concluded that aspirin's benefit-risk ratio is most favorable only in patients at high risk for CHD (10-year risk ≥6%), not moderate risk. The evidence showed that while aspirin reduced cardiovascular events, this benefit was offset by a 58% increase in major GI bleeding (OR 1.58) and increased hemorrhagic stroke risk.
The Evidence Evolution
Earlier guidelines from 2002-2009 3, 4, 5 did recommend aspirin for individuals with 10-year CHD risk ≥10%, which could include moderate-risk patients. However, these recommendations have been explicitly superseded by more recent trials showing that in the context of modern preventive therapies (statins, antihypertensives), aspirin's benefits are largely counterbalanced by bleeding risks 1, 6, 7.
Why the Other Statements Are Correct
A) Irreversible COX-1 Inhibition - TRUE
Aspirin irreversibly acetylates cyclooxygenase-1 in platelets 8, 9, 10, 11. This is the fundamental mechanism of its antiplatelet effect.
B) Proven Benefit in Established CVD - TRUE
Aspirin has well-established efficacy for secondary prevention in patients with established cardiovascular disease 12, 13, 1, 9. This is a Class I recommendation across all guidelines.
C) Increases GI Bleeding Risk - TRUE
Multiple high-quality studies confirm aspirin increases gastrointestinal bleeding risk by approximately 58-65% 2, 14. The 2016 USPSTF systematic review 2 found major GI bleeding increased with OR 1.58 (95% CI 1.29-1.95), and hemorrhagic stroke increased by 33% (OR 1.33).
D) Antiplatelet Effect Lasts 7-10 Days - TRUE
The antiplatelet effect persists for the lifespan of the platelet (7-10 days) because aspirin irreversibly inhibits COX-1 15. Studies show colonic bleeding times remain prolonged for up to 5 days after aspirin withdrawal, and clinical practice guidelines recommend discontinuation 4-7 days before high-risk endoscopic procedures 15.
Clinical Bottom Line
Current evidence-based practice restricts aspirin for primary prevention to:
- Very high-risk individuals (10-year ASCVD risk substantially >10%)
- Age 40-70 years only
- Low bleeding risk only
- After shared decision-making considering patient preferences 1, 7, 16
The blanket recommendation for moderate-risk individuals that characterized earlier guidelines has been abandoned based on contemporary trial evidence showing unfavorable benefit-risk ratios in this population 1, 2, 6, 7.