EvidenceAStrongGood randomized trials in people that agree, with no serious weaknesses. New studies are unlikely to change the answer.
For healthy people with no heart disease, low-dose aspirin now brings little net benefit and is not advised from age 60. For people who already had a heart attack or stroke, it still clearly helps.
Who it's for
People with past heart attack or stroke; not shown to help healthy older adults.
What to expect
Slightly fewer heart events in healthy adults, offset by more serious bleeding.
Watch out for
Serious stomach and other bleeding, more likely with age.
Aspirin lowers heart events but raises bleeding
Each dot is the combined result of many trials, with a line showing the range it could plausibly fall in.
← BetterWorse →
No difference
Heart attack, stroke or heart death0.89 (0.84 to 0.95)Clear improvement
In older adults aspirin did not cut heart disease but raised bleeding
Each dot is a result from one large trial of older adults, with a line for its range.
← BetterWorse →
No difference
Heart disease0.95 (0.83 to 1.08)No clear difference
Major bleeding1.38 (1.18 to 1.62)Clear worsening
Death from any cause1.14 (1.01 to 1.29)Probably worse
11.5
risk vs. placebo, 1 = same
In older adults aspirin did not cut heart disease but raised bleeding
Result
Estimate
95% range
Reading
Heart disease
0.95
0.83 to 1.08
No clear difference
Major bleeding
1.38
1.18 to 1.62
Clear worsening
Death from any cause
1.14
1.01 to 1.29
Probably worse
Sources 5 N Engl J Med, 2018; 7 N Engl J Med, 2018
What guidelines say
The US Preventive Services Task Force recommends against starting low-dose aspirin to prevent a first heart attack or stroke in adults 60 or older1Guideline · 2022Aspirin Use to Prevent Cardiovascular DiseaseThe USPSTF recommends against initiating low-dose aspirin use for the primary prevention of CVD in adults 60 years or older. (Grade D)US Preventive Services Task Force. For adults 40 to 59 with a 10% or greater 10-year risk of heart disease, starting is an individual decision with small net benefit, and people without increased bleeding risk who are willing to take it daily are more likely to benefit1Guideline · 2022Aspirin Use to Prevent Cardiovascular DiseaseThe USPSTF recommends against initiating low-dose aspirin use for the primary prevention of CVD in adults 60 years or older. (Grade D)US Preventive Services Task Force,6Guideline · 2022Aspirin Use to Prevent Cardiovascular Disease: US Preventive Services Task Force Recommendation Statement.(C recommendation) The USPSTF recommends against initiating low-dose aspirin use for the primary prevention of CVD in adults 60 years or older. (D recommendation).JAMA.
What the studies show
A review of 13 trials with 164,225 healthy adults (median age 62) found aspirin cut heart attacks, strokes and heart deaths by 11% relative to no aspirin. That is about 4 fewer events per 1,000 people over the follow-up period. Major bleeding rose 43%, about 5 more cases per 1,0002Meta-analysis · 2019 · 1,000 peopleAssociation of Aspirin Use for Primary Prevention With Cardiovascular Events and Bleeding Events: A Systematic Review and Meta-analysis.The use of aspirin in individuals without cardiovascular disease was associated with a lower risk of cardiovascular events and an increased risk of major bleeding. This information may inform discussions with patients about aspirin for primary prevention of cardiovascular events and bleeding.JAMA. These figures compare groups, so one person's gain depends on their starting risk.
An earlier review of 6 trials in 95,000 low-risk people found a 12% relative drop in serious vascular events. Deaths from vascular causes did not differ, and major bleeding rose4Meta-analysis · 2009 · 95,000 peopleAspirin in the primary and secondary prevention of vascular disease: collaborative meta-analysis of individual participant data from randomised trials.In primary prevention without previous disease, aspirin is of uncertain net value as the reduction in occlusive events needs to be weighed against any increase in major bleeds. Further trials are in progress.Lancet.
In a trial of 19,114 adults aged 70 or older, 100 mg aspirin over a median of 4.7 years did not significantly lower heart disease (a difference that could be chance). Major bleeding was 38% higher, 8.6 versus 6.2 per 1,000 person-years5Randomized trial · 2018 · 19,114 peopleEffect of Aspirin on Cardiovascular Events and Bleeding in the Healthy Elderly.The use of low-dose aspirin as a primary prevention strategy in older adults resulted in a significantly higher risk of major hemorrhage and did not result in a significantly lower risk of cardiovascular disease than placebo. (Funded by the National Institute on Aging and others; ASPREE ClinicalTrials.gov number,…N Engl J Med. Death from any cause was higher with aspirin, 12.7 versus 11.1 per 1,000 person-years, driven by cancer deaths. The authors called this unexpected and urged caution7Randomized trial · 2018 · 19,114 peopleEffect of Aspirin on All-Cause Mortality in the Healthy Elderly.Higher all-cause mortality was observed among apparently healthy older adults who received daily aspirin than among those who received placebo and was attributed primarily to cancer-related death. In the context of previous studies, this result was unexpected and should be interpreted with caution. (Funded by the…N Engl J Med.
In a trial of 15,480 adults with diabetes followed 7.4 years, aspirin cut serious vascular events (8.5% vs 9.6%) but raised major bleeding (4.1% vs 3.2%). The authors said the bleeding largely counterbalanced the benefit8Randomized trial · 2018 · 15,480 peopleEffects of Aspirin for Primary Prevention in Persons with Diabetes Mellitus.Aspirin use prevented serious vascular events in persons who had diabetes and no evident cardiovascular disease at trial entry, but it also caused major bleeding events. The absolute benefits were largely counterbalanced by the bleeding hazard. (Funded by the British Heart Foundation and others; ASCEND Current…N Engl J Med.
In a trial of 12,546 people at moderate risk, aspirin did not significantly reduce heart events over 5 years. Stomach bleeding was about twice as common (0.97% vs 0.46%)11Randomized trial · 2018 · 6,276 peopleUse of aspirin to reduce risk of initial vascular events in patients at moderate risk of cardiovascular disease (ARRIVE): a randomised, double-blind, placebo-controlled trial.The event rate was much lower than expected, which is probably reflective of contemporary risk management strategies, making the study more representative of a low-risk population. The role of aspirin in primary prevention among patients at moderate risk could therefore not be addressed. Nonetheless, the findings with…Lancet.
For people with existing disease, a pooled analysis of 287 studies found antiplatelet drugs cut serious vascular events by about a quarter. Benefits substantially outweighed the bleeding risk, and 75 to 150 mg daily worked at least as well as higher doses3Meta-analysis · 2002 · 1,000 peopleCollaborative meta-analysis of randomised trials of antiplatelet therapy for prevention of death, myocardial infarction, and stroke in high risk patients.Aspirin (or another oral antiplatelet drug) is protective in most types of patient at increased risk of occlusive vascular events, including those with an acute myocardial infarction or ischaemic stroke, unstable or stable angina, previous myocardial infarction, stroke or cerebral ischaemia, peripheral arterial…BMJ.
A secondary analysis of older adults with certain lipoprotein(a) gene variants suggested possible benefit. It was a subgroup A slice of the people in a study, such as only the women or only those over 65. Results in one slice are less reliable than the main result. finding and needs confirmation9Randomized trial · 2022Aspirin for Primary Prevention of Cardiovascular Events in Relation to Lipoprotein(a) Genotypes.Aspirin may benefit older individuals with elevated lipoprotein(a) genotypes in primary prevention.J Am Coll Cardiol.
Key studies
Study
Who
What it found
Review of 13 trials, 20192Meta-analysis · 2019 · 1,000 peopleAssociation of Aspirin Use for Primary Prevention With Cardiovascular Events and Bleeding Events: A Systematic Review and Meta-analysis.The use of aspirin in individuals without cardiovascular disease was associated with a lower risk of cardiovascular events and an increased risk of major bleeding. This information may inform discussions with patients about aspirin for primary prevention of cardiovascular events and bleeding.JAMA
164,225 adults without heart disease
Fewer heart events, more major bleeding
Trial, 20185Randomized trial · 2018 · 19,114 peopleEffect of Aspirin on Cardiovascular Events and Bleeding in the Healthy Elderly.The use of low-dose aspirin as a primary prevention strategy in older adults resulted in a significantly higher risk of major hemorrhage and did not result in a significantly lower risk of cardiovascular disease than placebo. (Funded by the National Institute on Aging and others; ASPREE ClinicalTrials.gov number,…N Engl J Med
19,114 adults 70 or older
No clear heart benefit; more bleeding
Trial, 20187Randomized trial · 2018 · 19,114 peopleEffect of Aspirin on All-Cause Mortality in the Healthy Elderly.Higher all-cause mortality was observed among apparently healthy older adults who received daily aspirin than among those who received placebo and was attributed primarily to cancer-related death. In the context of previous studies, this result was unexpected and should be interpreted with caution. (Funded by the…N Engl J Med
19,114 adults 70 or older
Higher death rate with aspirin, mostly cancer
Trial, 20188Randomized trial · 2018 · 15,480 peopleEffects of Aspirin for Primary Prevention in Persons with Diabetes Mellitus.Aspirin use prevented serious vascular events in persons who had diabetes and no evident cardiovascular disease at trial entry, but it also caused major bleeding events. The absolute benefits were largely counterbalanced by the bleeding hazard. (Funded by the British Heart Foundation and others; ASCEND Current…N Engl J Med
15,480 adults with diabetes
Fewer vascular events; more bleeding
Review of 287 studies, 20023Meta-analysis · 2002 · 1,000 peopleCollaborative meta-analysis of randomised trials of antiplatelet therapy for prevention of death, myocardial infarction, and stroke in high risk patients.Aspirin (or another oral antiplatelet drug) is protective in most types of patient at increased risk of occlusive vascular events, including those with an acute myocardial infarction or ischaemic stroke, unstable or stable angina, previous myocardial infarction, stroke or cerebral ischaemia, peripheral arterial…BMJ
High-risk patients
Aspirin protective after heart attack or stroke
Safety
Aspirin can cause severe stomach bleeding. The chance is higher at 60 or older, with past ulcers or bleeding problems, with blood thinners, steroids or other NSAIDs, with 3 or more drinks daily, or with higher or longer use than directed. It can also cause severe allergic reactions12Guideline · 2024Aspirin: FDA drug label (prescribing information)Warnings: Allergy alert : Aspirin may cause a severe allergic reaction, which may include: hives facial swelling shock asthma (wheezing) Stomach bleeding warning: This product contains an NSAID, which may cause severe stomach bleeding.US Food and Drug Administration. Anyone taking it daily should review it with their clinician.
What we don't know
Whether people with high lipoprotein(a) gene variants truly benefit; this rests on a subgroup analysis9Randomized trial · 2022Aspirin for Primary Prevention of Cardiovascular Events in Relation to Lipoprotein(a) Genotypes.Aspirin may benefit older individuals with elevated lipoprotein(a) genotypes in primary prevention.J Am Coll Cardiol.
Whether the higher cancer deaths in older adults are real; the authors urged caution7Randomized trial · 2018 · 19,114 peopleEffect of Aspirin on All-Cause Mortality in the Healthy Elderly.Higher all-cause mortality was observed among apparently healthy older adults who received daily aspirin than among those who received placebo and was attributed primarily to cancer-related death. In the context of previous studies, this result was unexpected and should be interpreted with caution. (Funded by the…N Engl J Med.
Written by AI from the studies listed, without review by a clinician, and graded with the GRADE method. It can be wrong, so check the studies it cites. Education, not medical advice.