Aspirin may help some adults prevent heart attacks
PHILADELPHIA -- The U.S. Preventive Services Task Force (USPSTF) today strongly recommended that doctors discuss the benefits and harms of aspirin therapy with adult patients who are at increased risk of coronary heart disease (CHD). The USPSTF recommends that people with a risk of three percent or higher of suffering a heart attack in the next five years should consider aspirin.
Those at risk include people with unfavorable cholesterol levels [elevated total cholesterol levels and/or low levels of high-density lipoprotein (HDL) cholesterol]; men over age 40; postmenopausal women, and people with risk factors for CHD, such as smoking, diabetes, and hypertension (high blood pressure). It is known that aspirin decreases the chances of heart attacks in people who have had previous heart attacks or strokes.
The new recommendations and a background article with a systematic review of the evidence about the harms and benefits of aspirin therapy are published in the January 15, 2002, issue of Annals of Internal Medicine. The optimum dose of aspirin for prevention is not known, according to the USPSTF. Doses of 75 mg daily, approximately the dose in one "baby" aspirin, appear as effective as higher doses. Uncontrolled hypertension may lessen the benefits of aspirin in reducing CHD.
However, the Task Force pointed out aspirin's potential harmful effects. It found good evidence that aspirin increases the incidence of gastrointestinal bleeding and found fair evidence that aspirin increases the incidence of hemorrhagic strokes (strokes caused by bleeding in the brain). Although the benefits of aspirin outweigh the harms for persons with an increased risk of CHD, the harms may exceed the benefits for those at low risk of CHD.
Because patients may have different views, physicians should discuss the benefits and harms of aspirin with each patient before deciding to use aspirin to prevent heart attacks.
Overall risk for coronary heart disease can be estimated by assessing a person's age, sex, blood pressure, cholesterol levels, and whether he or she smokes or has diabetes. The balance of benefits and harms of aspirin for preventing CHD shifts toward benefit with increasing risk for CHD. The benefits are clearest for those who have a three percent or greater chance of suffering a heart attack within five years, according to the USPSTF.
The USPSTF identified several free Internet calculators for determining levels of cardiovascular risk over a five- or 10-year period: www.med-decisions.com and http://hin.nhlbi.nih.gov/atpiii/calculator.asp?usertype=prof#moreinfo. These tools provide more accurate estimates of potential outcome than simply counting the number of risk factors.
"Aspirin therapy is powerful, and clinicians and patients need to discuss the role of aspirin therapy in combating CHD," said John M. Eisenberg, MD, director of the Agency for Healthcare Research and Quality (AHRQ), which sponsors the USPSTF. "This recommendation presents an ideal opportunity for clinicians to work with patients to determine the most appropriate therapy."
Three organizations have been influential in developing evidence-based guidelines for prevention of disease: the Canadian Task Force on the Periodic Health Examination, beginning in 1979; the American College of Physicians-American Society of Internal Medicine (ACP-ASIM), beginning in 1983; and the USPSTF, which issued its first report, Guide to Clinical Services, in 1989.
The guidelines of the three independent organizations have usually agreed closely, which "testifies to the robustness of a rigorous evidence-based approach to practice guideline development," said Harold C. Sox, MD, editor of Annals of Internal Medicine. Sox was also chairman of a previous USPSTF Task Force. ACP-ASIM has decided to limit its guideline development to areas the USPSTF does not address. It will defer to the USPSTF's recommendations for screening and for disease prevention. ACP-ASIM will soon release guidelines for treatment of headache and treatment of high blood pressure and high total cholesterol levels in diabetes patients.
The aspirin recommendation and a list of other topics under review by the USPSTF are available at the AHRQ Web site at http://www.ahrq.gov/clinic/3rduspstf/aspirin/" AHRQ is planning to compile all of the USPSTF chapters and evidence summaries in a notebook, "Guide to Clinical Preventive Services, Third Edition: Periodic Updates," which will be issued once or twice yearly. The recommendations on aspirin to prevent heart events can also be found on the Annals of Internal Medicine Web site, http://www.annals.org/.
NOTES TO EDITOR: Copies of the recommendations, "Aspirin for the Primary Prevention of Cardiovascular Events: Recommendations and Rationale," the summary of evidence background paper, and the editorial, "Disease Prevention Guidelines from the U.S. Preventive Services Task Force," can be obtained by calling the ACP-ASIM Communications Department at 1-800-523-1546, ext. 2656.
To contact AHRQ regarding the USPSTF recommendation, please call Farah Englert in Public Affairs (301-594-6372).
To contact Harold C. Sox, MD, Editor, Annals of Internal Medicine, please call ACP-ASIM Communications Department (215-351-2653).
CONTACT: Susan Anderson, 215-351-2653 or 800-523-1546, ext. 2653
Journal
Annals of Internal Medicine