Background: The role of aspirin in primary prevention of cardiovascular events remains controversial, Especially in diabetic patients. We have conducted a meta-analysis of all randomized controlled trials (RCTs) to evaluate the efficacy and safety of aspirin for primary prevention in diabetic patients.

Methods: Literature search of Pubmed, MEDLINE, Cochrane Library and for related RCTs that compared aspirin use versus placebo for primary prevention in diabetic patients, was conducted independently by two authors. All-cause mortality was the primary endpoint. Secondary endpoints were major adverse cardiovascular events (MACE), myocardial infarction (MI), cerebrovascular events, and bleeding events. We used a random effects model to report the risk ratios (RRs) with 95% confidence intervals (CIs).

Results: Our analysis included 7 RCTs (24,957 patients; 12,484 received aspirin and 12,473 received placebo). There was no significant reduction in all-cause mortality for patients treated with aspirin when compared with placebo (RR 0.94; 95% CI 0.87-1.01; P = 0.11). There were no significant differences between both groups in term of MI and cerebrovascular events (P > 0.05). Furthermore, aspirin was not associated with significantly higher incidence of bleeding (RR 1.57; 95% CI 0.85-2.90; P < 0.15). However, aspirin-treated patients significantly reduced MACE (RR 0.91; 95% CI 0.85-0.97; P = 0.006).

Conclusions: Aspirin use for primary prevention in diabetic patients has led to lower incidence of MACE without significant effect on cerebrovascular events, all-cause mortality, MI or bleeding events when compared with placebo. The decision regarding aspirin for primary prevention should be thoroughly discussed with patients given that there is no clear benefit in regard to risk reduction of cardiovascular disease.