A New Perspective in the Treatment of Dyslipidemia

Abstract

Patients with diabetes mellitus are at higher risk for cardiovascular events than those without diabetes. Furthermore, patients with diabetes have a characteristic 'lipid triad' of low high-density lipoprotein-cholesterol (HDL-C) levels, high triglyceride levels, and normal or slightly raised low-density lipoprotein-cholesterol (LDL-C) levels, with a preponderance of small, dense LDL-C particles. Current guidelines on preventing cardiovascular disease recognize the need not only to reduce LDL-C levels, but also to increase HDL-C and decrease triglyceride levels in diabetic patients. Some clinical trials of HMG-CoA reductase inhibitors (statins) have included large populations of diabetic patients. In some of these trials (such as 4S [Scandinavian Simvastatin Survival Study], CARE [Cholesterol and Recurrent Events] trial, and the HPS [Heart Protection Study]), HMG-CoA reductase inhibitor treatment significantly reduced cardiovascular events in diabetic patients, whereas in other trials (ALLHAT-LLT [Antihypertensive and Lipid-Lowering Treatment to Prevent Heart Attack Trial], ASCOT [Anglo-Scandinavian Cardiac Outcomes Trial]) the reductions were not significant. In CARDS (Collaborative Atorvastatin Diabetes Study), the first large HMG-CoA reductase inhibitor study to enroll only patients with type 2 diabetes, atorvastatin reduced cardiovascular events by 37% (p=0.001) compared with placebo. Fibric acid derivatives (fibrates), which are agonists of peroxisome proliferator-activated alpha receptors, exert their effects by altering the transcription of genes encoding proteins that control lipoprotein metabolism. Fibric acid derivatives are a valuable tool in the treatment of dyslipidemia in patients with diabetes, as they reduce plasma triglyceride levels by 30--50%, increase HDL-C levels by 10--15%, and shift the distribution of LDL subfractions towards larger, less atherogenic particles. The DAIS (Diabetes Atherosclerosis Intervention Study), which was conducted exclusively in patients with type 2 diabetes, found that fenofibrate reduces the progression of angiographic coronary artery disease. The VA-HIT (Veterans Affairs Cooperative Studies Program HDL-C Intervention Trial) showed that gemfibrozil reduced cardiovascular events in subgroups of diabetic patients. A large clinical event study, FIELD (Fenofibrate Intervention and Event Lowering in Diabetes), which is currently being completed, will provide further information on the value of fenofibrate for the reduction of cardiovascular risk in patients with diabetes.