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Final Research Plan

Aspirin Use for the Primary Prevention of Cardiovascular Events


The final Research Plan will be used to guide a systematic review of the evidence by researchers at an Evidence-based Practice Center. The resulting Evidence Report will form the basis of the USPSTF Recommendation Statement on this topic.

The draft Research Plan was available for comment from July 11 until August 7, 2013 at 5:00 p.m., ET. To view the draft Research Plan, click here.

A related final Research Plan on aspirin use for the primary prevention of cancer is available here.


I. Analytic Framework

Select Text Description below for details.

Abbreviations: CVD = cardiovascular disease; MI = myocardial infarction.

[D] Select for Text Description.

II. Key Questions to Be Systematically Reviewed

  1. Does regular aspirin use in persons without known cardiovascular disease reduce myocardial infarction (MI), stroke, death from MI or stroke, or all-cause mortality?
    1. Does the effect of aspirin vary between a priori subgroups, such as age, sex, smoking status, race/ethnicity, 10-year cardiovascular risk, or related risk conditions (e.g., diabetes mellitus, decreased ankle–brachial index, or elevated blood pressure)?
    2. Does the effect of aspirin vary by dose, formulation (enteric coated), or duration of use?
  2. Does regular aspirin use increase gastrointestinal bleeding, hemorrhagic stroke, or other serious harms (e.g., age-related macular degeneration)?
    1. Does the effect of aspirin vary by subgroup characteristics, such as age, sex, smoking status, race/ethnicity, 10-year cardiovascular risk, related risk conditions (e.g., diabetes mellitus, decreased ankle–brachial index, or elevated blood pressure), gastrointestinal bleeding or hemorrhagic stroke risk factors (including history of gastrointestinal bleeding, ulcers, or nonsteroidal anti-inflammatory drug use), or concomitant medication use (nonsteroidal anti-inflammatory drugs, selective serotonin reuptake inhibitors, or proton pump inhibitors)?
    2. Does the effect of aspirin vary by dose, formulation, or duration of use?

III. Contextual Questions

Contextual questions will not be systematically reviewed and are not shown in the Analytic Framework.

  1. Which of the accepted and available cardiovascular risk prediction tools commonly used in practice are good candidates to guide therapeutic decisionmaking for aspirin use?
    1. Do these cardiovascular risk prediction tools vary by subgroup?
  2. What are the characteristics of patient preferences with respect to the trade-off of the benefits and harms of aspirin chemoprevention (i.e., do patients value averted cardiovascular events more or less highly than incurred harms)?

IV. Research Approach

The Research Approach identifies the study characteristics and criteria that the Evidence-based Practice Center will use to search for publications and to determine whether identified studies should be included or excluded from the Evidence Report. Criteria are overarching as well as specific to each of the key questions (KQs).

  Included Excluded
Aim Primary prevention of cardiovascular disease: MI, stroke, death from MI or stroke, or all-cause mortality Secondary and tertiary prevention of MI, stroke, death from MI or stroke, or all-cause mortality
Populations Adults age 40 years and older without known cardiovascular disease Nonhuman populations; other selected nongeneralizable populations; patients with an existing cardiovascular disease diagnosis or history (heart failure, previous stroke, previous MI, transient ischemic attack, angina, or previous bypass or angioplasty); patients with atrial fibrillation; patients with familial hypercholesterolemia; patients with hypercoagulable disorders; children and young adults (age <40 years)
Interventions Regular oral aspirin use (minimum of 75 mg every other day); exposure of at least 12 months Nonaspirin antithrombotic medications; studies that do not provide information on dose; interventions limited to irregular or occasional use only; studies in which aspirin is a cotreatment; nonoral, nontablet forms of aspirin; exposure of less than 12 months
Comparisons Placebo or no treatment Any active substance or intervention (e.g., nonaspirin medication, dietary supplements, dietary change, weight loss)
Outcomes KQ 1: MI, stroke, death from MI or stroke, all-cause mortality, or quality of life

KQ 2: Gastrointestinal bleeding, hemorrhagic stroke, or other serious harms (e.g., age-related macular degeneration)

KQ 1: Intermediate markers of cardiovascular disease (e.g., calcium scores, intima media thickness, asymptomatic electrocardiography findings); intermediate markers of platelet function or clotting (e.g., in vitro clotting time, platelet aggregation)

KQ 2: Intermediate markers of platelet function or clotting

Study Design KQ 1: Randomized, controlled trials; controlled clinical trials; systematic reviews and meta-analyses of randomized, controlled trials

KQ 2: Randomized, controlled trials; controlled clinical trials; large prospective cohort studies

KQ 1: Observational studies (cohort, case control, case studies, or case series)

KQ 2: Case-control, case studies, or case series

Setting Outpatient Exclusively inpatient
Timing of outcome assessment 12 months or longer Less than 12 months
Country Any country with a 2013 Human Development Index of “Very High” Any country with less than a Human Development Index of “Very High”
Language English Languages other than English
Study Quality Good and fair quality, according to USPSTF criteria Poor quality, as defined by design-specific USPSTF criteria

V. Response to Public Comment

The draft Research Plan was posted for public comment on the U.S. Preventive Services Task Force (USPSTF) Web site from July 11 to August 7, 2013. The USPSTF reviewed and considered all comments received and made minor changes to the Research Plan in response. The age range for the population of interest was changed from persons age 18 years and older to persons age 40 years and older to better reflect the potential target population for the intervention. In addition, the term “regular” aspirin use was substituted for “low dose” aspirin use to avoid confusion. The variety of dosages used in the trials will be characterized in the evidence report.

AHRQ Publication No. 13-05195-EF-5
Current as of October 2013


Internet Citation:

U.S. Preventive Services Task Force. Aspirin Use for the Primary Prevention of Cardiovascular Events: Final Research Plan. AHRQ Publication No. 13-05195-EF-5. http://www.uspreventiveservicestaskforce.org/uspstaf13/asprcardio/asprcardfinalresplan.htm



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