This meta-analysis provides evidence for the significant associations between APOE ε4 mutation (ε3/ε4 vs. ε3/ε3; ε4/ε4 vs. ε3/ε3; ε4/ε4+ε3/ε4 vs. ε3/ε3; ε4 allele vs. ε3 allele) and an elevated risk of CAD in patients with T2DM. The gene discussed is APOE; the disease is type 2 diabetes mellitus.