Effectiveness and patient safety of platelet aggregation inhibitors in the prevention of cardiovascular disease and ischemic stroke in older adults – a systematic review

Platelet aggregation inhibitors (PAI) are among the most frequently prescribed drugs in older people, though evidence about risks and benefits of their use in older adults is scarce. The objectives of this systematic review are firstly to identify the risks and benefits of their use in the prevention and treatment of vascular events in older adults, and secondly to develop recommendations on discontinuing PAI in this population if risks outweigh benefits.

Staged systematic review consisting of three searches. Searches 1 and 2 identified systematic reviews and meta-analyses. Search 3 included controlled intervention and observational studies from review-articles not included in searches 1 and 2. All articles were assessed by two independent reviewers regarding the type of study, age of participants, type of intervention, and clinically relevant outcomes. After data extraction and quality appraisal we developed recommendations to stop the prescribing of specific drugs in older adults following the Grading of Recommendations Assessment Development and Evaluation (GRADE) methodology.

Overall, 2385 records were screened leading to an inclusion of 35 articles reporting on 22 systematic reviews and meta-analyses, 11 randomised controlled trials, and two observational studies. Mean ages ranged from 57.0 to 84.6 years. Ten studies included a subgroup analysis by age. Overall, based on the evaluated evidence, three recommendations were formulated. First, the use of acetylsalicylic acid (ASA) for primary prevention of cardiovascular disease (CVD) in older people cannot be recommended due to an uncertainty in the risk-benefit ratio (weak recommendation; low quality of evidence). Secondly, the combination of ASA and clopidogrel in patients without specific indications should be avoided (strong recommendation; moderate quality of evidence). Lastly, to improve the effectiveness and reduce the risks of stroke prevention therapy in older people with atrial fibrillation (AF) and a CHA₂DS₂-VASc score of ≥ 2, the use of ASA for the primary prevention of stroke should be discontinued in preference for the use of oral anticoagulants (weak recommendation; low quality of evidence).

The use of ASA for the primary prevention of CVD and the combination therapy of ASA and clopidogrel for the secondary prevention of vascular events in older people may not be justified. The use of oral anticoagulants instead of ASA in older people with atrial fibrillation may be recommended. Further high quality studies with older adults are needed.