May 20, 2005Open Access
Epidemiological modelling of routine use of low dose aspirin for the primary prevention of coronary heart disease and stroke in those aged ≥70
Key Result
Routine use of low dose aspirin in people aged ≥70 prevented MIs (-389 men, -321 women) but was offset by excess gastrointestinal (499 men, 572 women) and intracranial bleeding.
Structured PICO
Does routine use of low dose aspirin improve health outcomes in people aged ≥70 without overt cardiovascular disease?
P
Population
20,000 hypothetical subjects (10,000 men and 10,000 women) aged 70-74 with no overt cardiovascular disease, based on reference populations from Victoria, Australia.
I
Intervention
Routine use of low dose aspirin
C
Comparator
No aspirin (implied by epidemiological modelling of prevention versus adverse events)
O
Outcome
First ever myocardial infarction or unstable angina, ischaemic or haemorrhagic stroke, major gastrointestinal haemorrhage, and health adjusted years of life livedhard clinical
In a hypothetical population aged 70-74 without cardiovascular disease, the cardiovascular benefits of low-dose aspirin are offset by an increased risk of major bleeding.
Limitations
- Wide confidence intervals, indicating that the overall outcome could be beneficial or adverse
Abstract
OBJECTIVE: To investigate the routine use of low dose aspirin in people aged > or = 70 without overt cardiovascular disease. DESIGN: Epidemiological modelling in a hypothetical population. SETTING: Reference populations of men and women in the year 2000 from the state of Victoria, Australia. SUBJECTS: 10,000 men and 10,000 women aged 70-74 with no cardiovascular disease. MAIN OUTCOME MEASURES: First ever myocardial infarction or unstable angina, ischaemic or haemorrhagic stroke, and major gastrointestinal haemorrhage. Health adjusted years of life lived. RESULTS: The proportional benefit gained from the use of low dose aspirin by the prevention of myocardial infarctions (-389 in men, -321 in women) and ischaemic stroke (-19 in men and -35 in women) is offset by excess gastrointestinal (499 in men, 572 in women) and intracranial (76 in men, 54 in women) bleeding. The results in health adjusted years of life lived (which take into account length and quality of life) are equivocal for aspirin causing net harm or net benefit. CONCLUSION: Epidemiological modelling suggests that any benefits of low dose aspirin on risk of cardiovascular disease in people aged > or = 70 are offset by adverse events. These findings are tempered by wide confidence intervals, indicating that the overall outcome could be beneficial or adverse.