Abstract 1618: High-Density Lipoprotein Cholesterol but Not Apolipoprotein A-I or -II is Associated With Coronary Calcium in Type 2 Diabetes
Objectives: HDL-C is quite heterogeneous in both quality and function, particularly in type 2 diabetes, leading to challenges in cardiovascular risk prediction. We therefore tested whether the major HDL apolipoproteins (apo), apoA-I and -II, would be stronger predictors of coronary artery calcium (CAC), a measure of coronary atherosclerosis, in diabetic and non-diabetic study samples.
Methods: We performed cross-sectional analyses of asymptomatic Caucasian subjects in two community-based studies: the Penn Diabetes Heart Study [N=611 type 2 diabetic subjects, 71% men] and the Study of Inherited Risk of Coronary Atherosclerosis [N=803 non-diabetic subjects, 53% men)] using multivariate analysis of apoA-I, apoA-II, and HDL-C stratified by diabetes status.
Results: HDL-C was inversely correlated with CAC after adjustment for age, gender, and medications in type 2 diabetic [Tobit ratio for one standard deviation increase in HDL-C, 0.63 (95% CI 0.49 – 0.82), p=0.001] and non-diabetic Caucasians [0.71 (0.57– 0.87), p=0.001]. ApoA-I displayed a weaker inverse relationship in diabetic [0.76 (0.59 – 0.99), p=0.038] and non-diabetic subjects [0.76 (0.62– 0.94), p=0.013], while apoA-II had no significant association with CAC. In fully adjusted models, including additional cardiovascular risk factors, only HDL-C remained associated with CAC in the type 2 diabetic subjects. Furthermore, in combined analysis of diabetics and non-diabetics, HDL-C added value to apoA-I and -II in predicting CAC scores whereas the reverse was not true. Moreover, HDL-C added greater value than apoA-I and-II over apoB parameters.
Conclusions: HDL-C outperformed apoA-I or -II in predicting CAC with particular value in type 2 diabetic Caucasians. This suggests that, unlike incremental value in apoB measurement, perceived advantages in measuring apoA-I and -II may not translate into improved cardiovascular risk prediction beyond traditional, guideline-based HDL-C assessment.