Abstract 404: A Common Apolipoprotein A1 Polymorphism Predicts Racial Differences in Cardiovascular Outcomes
Background: Apolipoprotein A1 (apoA1) is the major apoprotein constituent of high-density lipoprotein cholesterol (HDL-C), which may be affected by a common polymorphism of a guanine (G) to adenine (A) substitution (G>A) at −75 bp in the apoA1 gene. The apo A1 polymorphism was previously shown to be associated with carotid artery stenosis in black but not white patients. We hypothesized that similar ethnic differences may exist regarding the apoA1 polymorphism and the risk of recurrent coronary events in post myocardial infarction (MI) patients.
Methods: The apoA1 −75G>A mutation was genotyped in a cohort of 916 post-MI patients including 145 African Americans and 771 white patients. The risk of recurrent coronary events (coronary-related death, non-fatal MI, or unstable angina) was prospectively studied during an average follow-up of 28 months.
Results: 30% of white and 22% of African American patients were identified as carriers of the high-risk allele of the apoA1 gene. The apoA1 polymorphism was associated with alterations in total cholesterol, triglyceride and HDL subfractions. Cox proportional-hazards regression analysis demonstrated that the presence of the Apo A1 −75G>A mutation was significantly associated with increased risk of recurrent cardiac events among black (HR =3.32, p=0.03) but not white (HR =1.13, p =0.64) patients. The Kaplan-Meier curves for recurrent cardiac events in African American patients by the presence of the apoA1 polymorphism are shown in the Figure⇓ below.
Conclusions: The apoA1 −75G>A polymorphism is associated with lipid alterations and a significantly increased risk of recurrent cardiac events among black but not white post-MI patients.