Aspirin to prevent cardiovascular events: Weighing risks and benefits

In general, men have twice the risk of GI bleeding compared with women.¹ The baseline number of GI bleeding events for individuals without a history of GI pain or bleeds taking daily aspirin is 4 per 10,000 person-years for women and 8 per 10,000 for men.¹ Patients with preexisting GI ulcers who receive daily aspirin have more than 2 to 3 times the baseline risk of serious GI bleeding.⁷ NSAIDs taken with daily aspirin can quadruple the risk of GI bleeding compared with aspirin use alone, although antacid therapy can reduce this risk.⁸ Co-administered anticoagulants (eg, warfarin) also significantly increase the risk—especially when compliance with medication and monitoring is poor. Aspirin also increases the risk of hematuria, easy bruising, and epistaxis.

Because consuming >3 standard drinks a day also increases the risk of GI bleeding by up to 6 fold, patients with untreated chronic alcohol abuse or dependence might not be good candidates for daily aspirin therapy.⁹ Contrary to popular belief and pharmaceutical marketing, enteric-coated tablets do not seem to reduce the risk of bleeding because aspirin impacts platelet function, not the lining of the stomach.

Table 1

USPSTF recommendations for daily aspirin use
in primary prevention of cardiovascular disease

Aspirin for psychiatric patients

Patients who have serious mental illness are at increased risk for CVD and often experience systemic barriers to receiving appropriate medical care.¹⁰ Psychiatrists can provide and advocate for primary care services for our patients, including daily aspirin use to prevent CVD when appropriate, and encourage a closer relationship with a primary care physician before an adverse event occurs. Aspirin use in psychiatric patients is associated with:

• potential drug-drug interaction with valproate¹¹
• mildly increased risk of bleeding as a result of reduced platelet function with the use of selective serotonin reuptake inhibitors.¹²

Balancing benefits vs risks. The USPSTF recommendation assumes that the value of preventing 1 MI or stroke is roughly equivalent to (or slightly less than) the cost of 1 GI bleeding event caused by aspirin. For example, among 1,000 men age 45 to 79 who have a ≥4% risk of MI over 10 years, 12.8 MIs would be prevented for every 8 GI bleeds caused by aspirin by following the current recommendations.¹

The USPSTF guidelines are based on average levels of risk for age and gender. Some men age <45 may decide that it is more important to avoid a cardiovascular event rather than an episode of GI bleeding and might choose to begin daily aspirin. Aspirin use should be discouraged in most patients at high risk for GI bleeding. The point where the potential benefits outweigh the risks must be determined on an individual basis ( Table 2 ).

Table 2

Aspirin to prevent cardiovascular disease and stroke:
When benefits outweigh risks

Related resources

• National Cholesterol Education Program. Online heart attack risk assessment tool. https://hp2010.nhlbihin.net/atpiii/calculator.asp.
• Framingham Heart study calculator. www.framinghamheartstudy.org/risk/coronary.html.
• National Cholesterol Education Program. www.nhlbi.nih.gov/health/public/heart/chol/wyntk.htm#risk.
• Colorado Neurological Institute. Online stroke risk assessment tool. www.thecni.org/Public/CNICenters/StrokeCenter/StrokeRiskCalculator/index.cfm.
• Agency for Healthcare Research and Quality. Fact sheet on aspirin to prevent cardiovascular disease. www.ahrq.gov/clinic/cvd/aspprovider.htm.

Drug brand names

• Valproate • Depacon
• Warfarin • Coumadin

Disclosures

Dr. Xiong reports no financial relationship with any company whose products are mentioned in this article or with manufacturers of competing products.

Dr. Kenedi receives grant/research support from Duke University Medical Center and Auckland University.