Comparison of lipid parameters to predict cardiovascular events in Japanese mild-to-moderate hypercholesterolemic patients with and without type 2 diabetes: Subanalysis of the MEGA study

Aims: To determine whether specific lipid parameters are better predictors of cardiovascular disease (CVD) in Japanese mild-to-moderate hypercholesterolemic patients with and without diabetes.

Methods: Mildly or moderately hypercholesterolemic patients with no history of CVD received diet therapy or diet therapy plus pravastatin. In this post-hoc subanalysis, 5-year data from 3170 patients (668 diabetes, 2502 non-diabetes) on diet therapy alone were used to compare lipid parameters as predictors of CVD. We examined the data by tertiles, using hazard ratio (HR) per one-standard deviation (SD) increment (decrease for high-density lipoprotein cholesterol, HDL-C), χ(2) value, receiver operating characteristic curve analysis, and spline analysis.

Results: In mild-to-moderate hypercholesterolemic patients with diabetes, increased total cholesterol (TC)/HDL-C, low-density lipoprotein cholesterol (LDL-C)/HDL-C and decreased HDL-C were strongly associated with increased incidence of CVD (tertile analysis). In non-diabetes, increased non-HDL-C, and LDL-C/HDL-C were significantly associated with increased incidence of CVD. A one-SD decrease in HDL-C and a one-SD increment in non-HDL-C, TC/HDL-C, and LDL-C/HDL-C were significantly associated with increased HRs for CVD in both diabetes and non-diabetes. Linear CVD risk increases were found for non-HDL-C in diabetes and for non-HDL-C and HDL-C in non-diabetes (spline analysis).

Conclusions: In mild-to-moderate hypercholesterolemia, CVD risk prediction by stratifications of single or combination of traditional lipid parameter values illustrates various patterns. Parameters including HDL-C are better predictors of cardiovascular risk than only using TC or LDL-C alone. Non-HDL-C could be the most useful lipid parameter to assess CVD risk, considering it is easy to calculate and less affected by food intake.