Background: There is no clear consensus on whether aspirin offers better outcomes in terms of secondary cardiovascular disease prevention compared with clopidogrel.
Objective: The aim of the study was to compare the safety and efficacy of clopidogrel versus aspirin in patients with established cardiovascular disease.
Methods: A systematic review of MEDLINE (via PubMed), Scopus, and Cochrane Library databases (last search date: August 28, 2021) was performed according to the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) statement for randomized control trials (RCTs) of clopidogrel versus aspirin as monotherapy in patients with established cardiovascular disease. Random-effects meta-analyses were performed.
Results: Five RCTs incorporating 26,855 patients (clopidogrel: 13,426; aspirin: 13,429) were included. No statistically significant difference was observed between clopidogrel and aspirin in terms of all-cause mortality (odds ratio [OR]: 1.01 [95% confidence interval, CI: 0.91-1.13]; p = 0.83), ischemic stroke (OR: 0.87 [95% CI: 0.71-1.06]; p = 0.16), and major bleeding rates (OR: 0.77 [95% CI: 0.56-1.06]; p = 0.11). Patients receiving clopidogrel had borderline lower risk for major adverse cardiovascular events (MACE) (OR: 0.84 [95% CI: 0.71-1.00]; p = 0.05) and lower risk for nonfatal myocardial infarction (OR: 0.83 [95% CI: 0.71-0.97]; p = 0.02, relative risk reduction = 16.9%, absolute risk reduction = 0.5%, number needed to treat = 217 for a mean period of 20 months) compared with patients receiving aspirin.
Conclusion: In patients with established cardiovascular disease, clopidogrel was associated with a 17% relative-risk reduction for nonfatal MI, borderline decreased risk for MACE, and similar risk for all-cause mortality, stroke, and major bleeding compared with aspirin.
Protocol registration: PROSPERO CRD42021283866.
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