Apolipoprotein e4 allele is predictor of coronary artery disease death in elderly patients with type 2 diabetes mellitus

The presence of the apolipoprotein (Apo) e4 allele is reported to be associated with the increased risk of coronary artery disease (CAD), as well as the impairment of endothelium-dependent dilation in type 2 diabetes mellitus. Therefore, we hypothesized that the Apo e4 allele increases the death risk from coronary artery disease in type 2 diabetes. From January 1993 to December 1999, 36 type 2 diabetic patients with e4/4 or e4/3, 62 with e3/3 and 33 with e2/2 or e3/2 genotypes were recruited. All subjects were unrelated, elderly, type 2 diabetic patients with coronary artery disease, aged 60–84 years, with cardiac function at the Class I stage at time of enrolment. A follow-up study of 3–10 years was undergone. The results are as follows: At baseline, serum total cholesterol and low density lipoprotein (LDL) cholesterol concentrations were higher in subjects with e4/3 or e4/4 than in subjects with e2/2 or e3/2 (P=0.026). Lipoprotein(a) concentration was lower in subjects with e2/2 or e3/2 than in subjects with e3/3 (P=0.044) and e4/3 or e4/4 (P=0.038). During the 3–10 years follow-up period, a total of 39 patients who died from CAD was recorded in this sample. Compared with patients with e3/3 (P=0.030) and patients with e2/2 or e3/2 genotypes (P=0.001), the mortality rate of CAD in patients with e4/3 or e4/4 genotypes was the highest (50%). Stepwise discriminant analysis revealed that in the diabetic population studied the Apo e4 allele was independently and significantly associated with CAD death (B=0.64). However, the strength of the association decreased (B=0.48) when total cholesterol, LDL-cholesterol and lipoprotein(a) were included in the model. Therefore, we concluded that Apo e4 allele increases the risk of CAD death in elderly patients with type 2 diabetes mellitus.