The aspirin controversy in primary prevention

Area of Science:

• Cardiology
• Preventive Medicine
• Clinical Pharmacology

Background:

• Conflicting meta-analysis results on aspirin's role in primary cardiovascular disease prevention necessitate a critical evaluation.
• Previous meta-analyses, including the 2002 Antithrombotic Trialists' Collaboration, indicated aspirin reduces cardiovascular events, primarily nonfatal myocardial infarction (MI).

Purpose of the Study:

• To review and critically evaluate meta-analysis results comparing aspirin with placebo for primary cardiovascular disease prevention.
• To determine if aspirin provides a net benefit in primary cardiovascular disease prevention.

Main Methods:

• Review of four independent meta-analyses conducted between 2009 and 2012.
• Inclusion of studies involving a large population (95,000–102,621 individuals) at low risk for cardiovascular disease.

Main Results:

• Consistent findings across meta-analyses show aspirin reduces nonfatal myocardial infarction (MI).
• No definitive evidence supports aspirin reducing cardiovascular mortality, though a modest reduction in all-cause mortality is suggested.
• Aspirin decreases ischemic stroke risk but increases hemorrhagic stroke and major bleeding events.

Conclusions:

• In low-risk individuals, aspirin use reduces MI risk but increases major bleeding.
• A modest, nominally significant reduction in total mortality is observed with aspirin.
• Individualized recommendations for aspirin in primary prevention are crucial, considering patient-specific benefits, risks, values, and preferences.