Authors' objectives:

To examine the benefits and harms of aspirin chemoprevention.

Authors' results and conclusions: When indicated, we performed meta-analysis using the DerSimonian and Laird random effects model. We then used the quantitative results of our review to model the consequences of treating patients with different levels of baseline coronary heart disease (CHD) risk. We identified five trials that examined the effect of aspirin on cardiovascular events in patients with no previous CVD. For patients similar to those enrolled in the trials, aspirin reduces the risk for the combined endpoint of nonfatal myocardial infarction and fatal coronary heart disease (CHD) by 28 percent (summary OR, 0.72; 95 percent CI, 0.60 to 0.87). Aspirin increased the risk of hemorrhagic strokes (summary OR, 1.4; 95 percent CI, 0.9 to 2.0) and major gastrointestinal bleeding (summary OR, 1.7; 95 percent CI, 1.4 to 2.1). All-cause mortality (summary OR, 0.93; 95 percent CI, 0.84 to 1.02) was not significantly affected over this time period. For 1,000 patients with a 5 percent risk of CHD events over 5 years, aspirin would prevent 14 myocardial infarctions (range 6 to 20) but would cause 1 hemorrhagic stroke (range 0 to 2) and 3 major gastrointestinal bleeds (range 2 to 4). For patients with CHD risk of 1 percent over 5 years, aspirin would prevent 3 myocardial infarctions (range 1 to 4) but would cause 1 hemorrhagic stroke (range 0 to 2) and 5 major gastrointestinal bleeding events (range 2 to 4).

Authors' recommendations: Aspirin can prevent myocardial infarctions but increases the risk of gastrointestinal bleeding and appears to increase the risk of hemorrhagic stroke. The net benefit of aspirin increases with increasing cardiovascular risk. The decision about whether to use aspirin chemoprevention requires consideration of the patient's cardiovascular risk as well as the patient's relative utility for the different clinical outcomes prevented or caused by its use.

Authors' methods: Systematic review

Project Status: Completed

URL for project: http://www.ahrq.gov/clinic/uspstf/uspsasmi.htm

Year Published: 2002

English language abstract: An English language summary is available

Publication Type: Not Assigned

Country: United States

Organisation Name: Agency for Healthcare Research and Quality

Contact Address: Center for Outcomes and Evidence Technology Assessment Program, 540 Gaither Road, Rockville, MD 20850, USA. Tel: +1 301 427 1610; Fax: +1 301 427 1639;

Contact Name: martin.erlichman@ahrq.hhs.gov

Contact Email: martin.erlichman@ahrq.hhs.gov

Copyright: Agency for Healthcare Research and Quality (AHRQ)