In both CAD patients with age < 65 years and age ≥ 65 years there was no significant difference in distributions of gender and BMI, and proportions of history of smoking, history of alcohol consumption, and diabetes mellitus, and serum lipid‐lipoprotein levels among different CYP2C19 phenotypes, respectively (all p > 0.05) (Table 4). This evidence concerns the gene CYP2C19 and diabetes mellitus.