Data sources, eligibility, and Data extraction
We searched in Medline (via PubMed), Cinahl (via Ebsco), Scopus, and Web
of Sciences until December 2020 using the predefined search terms
aspirin, cardiovascular disease (CVD), diabetes, efficacy, OR
meta-analysis until December 2020. Ten trials included in a previous
meta-analysis; 12 were also identified and included in
the present meta-analysis. The inclusion criteria include only
randomized clinical trials of Aspirin, except one which was a
cross-sectional study. The Aspirin was compared with placebo or no
treatment in patients with or without diabetes, and without a history or
clinical evidence of CVD; screened for the eligibility. Studies had to
be controlled (placebo or control group) but could be open-label or
blinded. The patients above 18 years of age either who have diabetes was
included, and full text was acquired for further evaluation if the
citation was deemed pertinent. Studies were excluded if the patient was
below 18 years of age, non-randomized studies comparing Aspirin with
another antiplatelet agent, or use of Aspirin in combination with any
other antiplatelet drug compared with placebo.
The data extracted from the selected trials included appropriate
study-level information on type of study design; baseline of the study
period, source of participants; total population including proportion of
men; location; age range at baseline; allocation concealment; blinding;
intervention and dosage; medication compliance; duration of the therapy,
completeness of follow-up and also included trial population with
diabetes as described in Table 1.
The quality of risk involved was assessed using the QUADAS-2 (Quality
Assessment of Diagnostic Accuracy Studies 2) criterion. If any
disagreement arose, it was resolved by consensus among
reviewers24.
The outcomes of major adverse cardiovascular event/s [MACE; defined as
a combination of nonfatal myocardial infarction (MI), nonfatal stroke
and cardiovascular death], other cardiovascular outcomes, all-cause
mortality, and adverse events; and risk estimates were also evaluated in
diabetic patients to rule out the efficacy of Aspirin to placebo.