David Didden, MD

ABSTRACT

BACKGROUND: In patients with known cardiovascular disease aspirin has well-established benefits, including improved outcomes of ischemic CHD, stroke, and all-cause mortality. Because of their lower risk, it is less clear whether using aspirin for preventing cardiovascular disease is beneficial in patients without preexisting disease.

POPULATION STUDIED: This meta-analysis reviewed studies that evaluated the role of aspirin in patients with no previous history of cardiovascular disease, including myocardial infarction (MI), stroke, angina, transient ischemic attack, and peripheral vascular disease. The authors excluded trials in which more than 10% of participants had diagnosed vascular disease. Of the approximately 50,000 patients included, most were middle-aged men.

STUDY DESIGN AND VALIDITY: This study was a meta-analysis of RCTs used as evidence for the US Preventive Services Task Force (USPSTF) in developing recommendations for the use of aspirin in the primary prevention of cardiovascular disease. The authors conducted a MEDLINE search for RCTs comparing aspirin with placebo (or simply no aspirin) in patients with no previous history of cardiovascular disease; these studies measured the outcomes of MI, stroke, and mortality. The authors included case-control and systematic reviews or meta-analyses in addition to RCTs to assess any harm of aspirin use (eg, rates of hemorrhagic stroke or gastrointestinal bleeding).

OUTCOMES MEASURED: The authors combined data from the RCTs for the following outcomes: total CHD events, (defined as nonfatal MI or death due to CHD), stroke, and all-cause mortality. For assessing adverse effects of aspirin, the investigators extracted rates of hemorrhagic stroke and major gastrointestinal bleeding events.

RESULTS: Patients taking aspirin had a lower risk of a CHD event (odds ratio [OR] = 0.72; 95% CI, 0.60 -0.87), which equates to a number needed to treat (NNT) of 195 patients to prevent 1 nonfatal MI or death due to CHD. For comparison, treatment of severe hypertension benefits 1 in 15 patients, but treatment of mild hypertension benefits 1 in 700 treated patients. In their subgroup analysis the authors found that the effect of aspirin in preventing CHD events in women was smaller than in men and not statistically significant. They concluded that it remains unclear as to whether gender influences the effects of aspirin. Regarding prevention of stroke and all-cause mortality, there was no significant benefit in taking aspirin.

ABSTRACT

BACKGROUND: In patients with known cardiovascular disease aspirin has well-established benefits, including improved outcomes of ischemic CHD, stroke, and all-cause mortality. Because of their lower risk, it is less clear whether using aspirin for preventing cardiovascular disease is beneficial in patients without preexisting disease.

POPULATION STUDIED: This meta-analysis reviewed studies that evaluated the role of aspirin in patients with no previous history of cardiovascular disease, including myocardial infarction (MI), stroke, angina, transient ischemic attack, and peripheral vascular disease. The authors excluded trials in which more than 10% of participants had diagnosed vascular disease. Of the approximately 50,000 patients included, most were middle-aged men.

STUDY DESIGN AND VALIDITY: This study was a meta-analysis of RCTs used as evidence for the US Preventive Services Task Force (USPSTF) in developing recommendations for the use of aspirin in the primary prevention of cardiovascular disease. The authors conducted a MEDLINE search for RCTs comparing aspirin with placebo (or simply no aspirin) in patients with no previous history of cardiovascular disease; these studies measured the outcomes of MI, stroke, and mortality. The authors included case-control and systematic reviews or meta-analyses in addition to RCTs to assess any harm of aspirin use (eg, rates of hemorrhagic stroke or gastrointestinal bleeding).

OUTCOMES MEASURED: The authors combined data from the RCTs for the following outcomes: total CHD events, (defined as nonfatal MI or death due to CHD), stroke, and all-cause mortality. For assessing adverse effects of aspirin, the investigators extracted rates of hemorrhagic stroke and major gastrointestinal bleeding events.

RESULTS: Patients taking aspirin had a lower risk of a CHD event (odds ratio [OR] = 0.72; 95% CI, 0.60 -0.87), which equates to a number needed to treat (NNT) of 195 patients to prevent 1 nonfatal MI or death due to CHD. For comparison, treatment of severe hypertension benefits 1 in 15 patients, but treatment of mild hypertension benefits 1 in 700 treated patients. In their subgroup analysis the authors found that the effect of aspirin in preventing CHD events in women was smaller than in men and not statistically significant. They concluded that it remains unclear as to whether gender influences the effects of aspirin. Regarding prevention of stroke and all-cause mortality, there was no significant benefit in taking aspirin.

ABSTRACT

BACKGROUND: In patients with known cardiovascular disease aspirin has well-established benefits, including improved outcomes of ischemic CHD, stroke, and all-cause mortality. Because of their lower risk, it is less clear whether using aspirin for preventing cardiovascular disease is beneficial in patients without preexisting disease.

POPULATION STUDIED: This meta-analysis reviewed studies that evaluated the role of aspirin in patients with no previous history of cardiovascular disease, including myocardial infarction (MI), stroke, angina, transient ischemic attack, and peripheral vascular disease. The authors excluded trials in which more than 10% of participants had diagnosed vascular disease. Of the approximately 50,000 patients included, most were middle-aged men.

STUDY DESIGN AND VALIDITY: This study was a meta-analysis of RCTs used as evidence for the US Preventive Services Task Force (USPSTF) in developing recommendations for the use of aspirin in the primary prevention of cardiovascular disease. The authors conducted a MEDLINE search for RCTs comparing aspirin with placebo (or simply no aspirin) in patients with no previous history of cardiovascular disease; these studies measured the outcomes of MI, stroke, and mortality. The authors included case-control and systematic reviews or meta-analyses in addition to RCTs to assess any harm of aspirin use (eg, rates of hemorrhagic stroke or gastrointestinal bleeding).

OUTCOMES MEASURED: The authors combined data from the RCTs for the following outcomes: total CHD events, (defined as nonfatal MI or death due to CHD), stroke, and all-cause mortality. For assessing adverse effects of aspirin, the investigators extracted rates of hemorrhagic stroke and major gastrointestinal bleeding events.

RESULTS: Patients taking aspirin had a lower risk of a CHD event (odds ratio [OR] = 0.72; 95% CI, 0.60 -0.87), which equates to a number needed to treat (NNT) of 195 patients to prevent 1 nonfatal MI or death due to CHD. For comparison, treatment of severe hypertension benefits 1 in 15 patients, but treatment of mild hypertension benefits 1 in 700 treated patients. In their subgroup analysis the authors found that the effect of aspirin in preventing CHD events in women was smaller than in men and not statistically significant. They concluded that it remains unclear as to whether gender influences the effects of aspirin. Regarding prevention of stroke and all-cause mortality, there was no significant benefit in taking aspirin.