Daily Low-dose Aspirin Therapy: Pros & Cons

InBrief

by Madeleine Beckman

Edited by Richard Strongwater, MD

Some 30-million Americans who are at least 40 years old take a small daily dose of aspirin (81 mg) in an attempt to prevent cardiovascular disease, cancer, and even dementia. Of these individuals, over 6-million Americans self-medicate with aspirin each day, taking the drug without a doctor’s recommendation.

The Argument

Pro: A low daily dose of aspirin thins the blood, which can help prevent heart disease and clots that may lead to a heart attack or stroke.

Con: This same low daily dose of aspirin may increase the risk of hemorrhagic stroke, gastrointestinal bleeding, and stomach-ulcer development.

The use of daily low-dose aspirin therapy is a complex issue. In 2018, the results of three major clinical trials prompted the American Heart Association (AHA) and the American College of Cardiology (ACC) to change clinical practice guidelines, recommending against routine use of aspirin in people over age 70 and individuals at increased risk of bleeding with no existing cardiovascular disease (CVD). In March 2019, the AHA and the ACC recommended against routine use of low-dose aspirin in people at greater risk of bleeding (eg, those with peptic ulcer) and in persons at least 70 years of age without either existing heart disease or history of stroke.

Recently, guidelines from the US Preventive Services Task Force stated that low-dose aspirin therapy was recommended for “…the primary prevention of CVD and colorectal (CRC) cancer in adults aged 50 to 59 years who have a 10 per cent or greater 10-year CVD risk, are not at increased risk for bleeding, have a life expectancy of at least 10 years, and are willing to take low-dose aspirin daily for at least 10 years.” The report also noted that low-dose daily aspirin is still indicated to help reduce repeated heart attacks and strokes.

In a study recently published in the Journal of the American Medical Association, Zheng and others examined aspirin’s preventive benefits against cancer, finding “no overall association between aspirin use and incidence of cancer or cancer mortality…The findings of this study suggest that the association of aspirin with cancer outcomes is neutral, with no suggestion of harm or benefit from the available current evidence.” The authors also wrote that aspirin use “appears to reduce the risk ofCRC incidence after a latency period of approximately 10 years. The effect on CRC mortality was similar.”

First, Do No Harm

Results of the meta-analysis A Study of Cardiovascular Events in Diabetes (ASCEND)concluded that since early trials showed aspirin benefits in certain populations, the risk of vascular events (ie, myocardial infarction, stroke, cardiovascular death) in secondary prevention populations has fallen. Although significant, these and similar findings may still present difficulties for physicians who advise patients not at risk for CVD to refrain from taking preventative aspirin.

The American Medical Association recommends that physicians ask patients if they are taking unprescribed daily aspirin and advise them about the benefits versus risks. Instead of taking a baby aspirin, persons not at risk should consume a heart-healthy diet, exercise regularly, control blood pressure and cholesterol (including use of a statin, if indicated), quit smoking, and maintain a healthy weight.

Takeaway for Patients

Patients should not self-medicate with aspirin. Instead, they should consult with their physicians about starting low-dose aspirin therapy. Further, suddenly stopping low-dose aspirin therapy may have a rebound effect that could trigger a blood clot and increase the risk of a heart attack. Therefore, anyone deciding to stop self-prescribed aspirin therapy should speak with a physician before making changes that may result in serious consequences.

Editor’s note: When a patient asks me about stopping low-dose aspirin that was started without medical consultation for primary prevention, I am reluctant to stop it, especially if the patient has at least two major cardiovascular risk factors (eg, family history for cardiovascular disease, high blood pressure, dyslipidemia, diabetes, smoking, obstructive sleep apnea, obesity). If I am in doubt, I obtain an ultrasound of the carotid arteries to determine the degree of atherosclerotic plaque and/or a coronary calcium score by computed tomography scan to help identify an additional layer of risk.

References

1. Agence France-Presse. The pros and cons of a daily aspirin: good for heart disease but it raises risk of internal bleeding. South China Morning Post Web site SCMP.com. January 24, 2020. Accessed March 2, 2020.

2. American Heart Association News. Avoid daily aspirin unless your doctor prescribes it, new guidelines advise. American Heart Association Web site. https://www.heart.org/en/news/2019/03/18/avoid-daily-aspirin-unless-your-doctor-prescribes-it-new-guidelines-advise. March 18, 2019. Accessed March 2, 2020.

3. ASCEND Study Collaborative Group, Bowman L, Mafham M, et al. Effects of aspirin for primary prevention in persons with diabetes mellitus. N Engl J Med. 2018;379:1529-1539.

4. Berg S. New heart-disease prevention guideline: what physicians must know. American Heart Association Web site. https://www.ama-assn.org/delivering-care/hypertension/new-heart-disease-prevention-guideline-what-physicians-must-know. March 28, 2019. Accessed March 2, 2020.

5. Final Recommendation Statement: Aspirin Use to Prevent Cardiovascular Disease and Colorectal Cancer: Preventive Medication. U.S. Preventive Services Task Force Web site www.usreventitiveServiceTaskForce.org. September 2017. Accessed March 2, 2020.

6. Grisham J. Does an aspirin a day reduce the risk of colorectal cancer? Memorial Sloan Kettering Cancer Center Web site, www.mskcc.org March 21, 2017. Accessed March 2, 2020.

7. Hart RJ, Halperin JL, McBride R, et al. Aspirin for the primary prevention of stroke and other major vascular events: meta-analysis and hypotheses. Arch Neurol. 2000;57:326-332.

8. Huang WY, Saver JL, Wu YL, Lin CJ, Lee M, Ovbiagele B. Frequency of intracranial hemorrhage with low-dose aspirin in individuals without symptomatic cardiovascular disease: a systematic review and meta-analysis. JAMA Neurol.2019 [Epub ahead of print].

9. Mahmoud AN, Gad MM, Elgendy AY, Elgendy IY, Bavry AA. Efficacy and safety of aspirin for primary prevention of cardiovascular events: a meta-analysis and trial sequential analysis of randomized controlled trials. Eur Heart J.2019;40:607-617.

10. Mayo Clinic Staff. Daily aspirin therapy: understand the benefits and risks. Mayo Clinic Web site. www.mayoclinic.org. January 9, 2019. Accessed March 2, 2020.

11. McNeil JJ, Woods RL, Nelson MR, et al. Effect of aspirin on disability-free survival in the healthy elderly. N Engl J Med.2018;379:1499-1508.

12. O'Brien CW, Juraschek SP, Wee CC. Prevalence of aspirin use for primary prevention of cardiovascular disease in the United States: results from the 2017 National Health Interview Survey. Ann Intern Med. 2019;171:596-598.

13. Ranger GS, McKinley-Brown C, Rogerson E, Schimp-Manuel K. Aspirin use, compliance, and knowledge of anticancer effect in the community. Perm J.2020;24: 19.116.

14. Zheng SL, Roddick AJ. Association of aspirin use for primary prevention with cardiovascular events and bleeding events: a systematic review and meta-analysis. JAMA.2019;321:277-287.