Dyslipidemias in diabetes

Abstract

Cardiovascular diseases (CVD) are responsible for 75% of the morbidity and mortality in patients with type 2 diabetes. Diabetes accelerates plaque formation and progression in coronary, cerebrovascular and peripheral arteries. Patients with diabetes obtain less benefit from invasive procedures such as angioplasty and coronary revascularization than do patients without diabetes. Survival following a cardiovascular event is lower in patients with diabetes, particularly in women. It is estimated that 50% of patients have CVD at the time of diagnosis with diabetes. This emphasizes the importance of early diagnosis and aggressive treatment of comorbidities and risk factors. Dyslipidemias in diabetes are characterized by elevated triglycerides, small dense LDL, and decreased HDL. The atherosclerotic process is associated with inflammatory changes with deposition of lipids in the arterial walls. Diabetes also accelerates this process by altering the structure and function of circulating lipoproteins. In a seven year study in a population in Finland, the incidence of myocardial infarctions (MI) in patients with diabetes without a prior MI was similar to patients without diabetes but with a previous MI. Thus, there is a linkage between diabetes and CVD at epidemiologic and pathophysiologic levels, and the National Cholesterol Education Program Adult Treatment Panel (NCEP ATP-III) designated diabetes as a CVD risk equivalent. Treatment of LDL cholesterol is the first priority, followed by HDL and triglycerides: the goals are LDL < 100 mg/dL, HDL > 40 mg/dL in men or HDL > 50 mg/dL in women, and triglycerides < 150 mg/dL. Statins are the drugs of choice. Benefits of aggressive lipid management with statins have been shown in primary prevention studies (AFCAPS /TexCAPS, ASCOT) and secondary prevention studies (4S, CARE, LIPID, HPS) in patients with varying degrees of dyslipidemias and other risk factors. The Heart Protection Study (HPS) has shown that high risk patients benefit from statins regardless of the LDL levels. Other drugs, e.g., fibrates, nicotinic acid, bile acid sequestrants have a role in selected patients. A new class of drag, ezetimibe, blocks cholesterol absorption in the gastrointestinal tract: it is synergistic with the statins and effective as a single agent when statins are contraindicated. Aggressive therapy to treat diabetic dyslipidemias has been shown to reduce the risk of CVD.