Management of dyslipidemias in the presence of the metabolic syndrome or type 2 diabetes

Abstract

In the metabolic syndrome and type 2 diabetes, excess energy intake on the background of genetic predisposition and lifestyle factors leads to the dysregulation of fatty acid metabolism and acquired insulin resistance. These initial metabolic defects are reflected to both lipoprotein and glucose metabolism and contribute to increased risk for cardiovascular disease. However, even after controlling for the traditional cardiovascular risk factors, subjects with the metabolic syndrome and type 2 diabetes remain at high residual cardiovascular risk despite of low/normal LDL-cholesterol concentration. For 2 decades, statin therapy has been the cornerstone of treatment of dyslipidemia in these disorders. In the metabolic syndrome and type 2 diabetes, only statin treatment has demonstrated consistently a significant reduction in cardiovascular and all cause mortality in clinical trials. Lately, increased incidence of diabetes especially in the high-risk populations using statins has raised the debate whether statins are indicated for primary prevention especially in the metabolic syndrome. Guidelines recommend intensified lifestyle intervention to those in high risk groups on statin therapy to reduce the residual risk. Despite of the proven efficacy on plasma lipids, fibrate, or niacin as monotherapy, or in combination with statins has failed in reducing cardiovascular mortality. This underlies the fact that improvement in dyslipidemia or other biomarkers is not equal to the reduction in cardiovascular events. However, fibrates in combination with statins seem to be beneficial to reduce CVD events in subjects with low HDL-cholesterol (< 0.9-1.1 mmol/L) and elevated triglycerides (> 2.3 mmol/L), but the data are derived from subgroup analysis of clinical trials. The position of niacin and ezetimibe and omega-3 fatty acids in treatment of dyslipidemia in the metabolic syndrome and type 2 diabetes is even less clear and remains to be established in future clinical trials.