The lipid triad in type 2 diabetes - Prevalence and relevance of hypertriglyceridaemia/low high-density lipoprotein syndrome in type 2 diabetes

Cardiovascular disease is the major cause of morbidity and mortality in type 2 diabetes mellitus. Among the established risk factors, the lipid triad (elevated triglycerides, decreased high-density lipoprotein cholesterol, and small dense low-density lipoprotein cholesterol) is a powerful risk factor for atherosclerosis in type 2 diabetes. The prevalence of hypertriglyceridaemia (HTG) in type 2 diabetes is two to three times higher than in non-diabetics. The Copenhagen Male study, the AMORIS study, and several other trials showed hypertriglyceridaemia to be an independent predictor of coronary heart disease (CHD). HTG may promote risk both directly and indirectly through association with alterations of lipoprotein size and composition. The Veterans Affairs High-Density Lipoprotein Cholesterol Intervention Trial (VA-HIT) demonstrated that raising high-density lipoprotein cholesterol (HDL-C) in patients with low (HDL-C) and low-density lipoprotein cholesterol (LDL-C) is associated with a significant reduction in CHD risk. It was shown in the Diabetes Intervention Study, AFCAPS/TexCAPS, and PROCAM studies that decreased HDL-C and elevated triglycerides are independent risk factors for atherosclerosis, particularly in patients with diabetes mellitus. Several epidemiological studies demonstrated that total cholesterol/high-density lipoprotein cholesterol (TC/HDL-C) ratios or low-density lipoprotein cholesterol/high-density lipoprotein cholesterol (LDL-C/HDL-C) ratios could be better predictors of atherosclerosis than any single lipid parameter. Intima-media thickness (IMT), a well established marker of early atherosclerosis, is associated with HTG/low HDL-cholesterol. In the Risk factors in IGT for Atherosclerosis and Diabetes (RIAD) study total and HDL-cholesterol were independent determinants of IMT in subjects at risk for type 2 diabetes. Postprandial HTG was also shown to be correlated with increased IMT in type 2 diabetic patients.