Diabetes and dyslipidemia.

Abstract

Numerous prospective cohort studies have indicated that diabetes mellitus (DM), particularly type-2 DM (the type of diabetes associated with insulin resistance that usually strikes adults), is associated with a 3-4-fold increase in risk for coronary heart disease (CHD) [1-3]. The increase in risk is particularly evident in younger-age groups, and in women: females with type-2 DM appear to lose a great deal of the protection that characterizes non-diabetic females. Furthermore, patients with DM have a 50% greater in-hospital mortality, and a 2-fold increased rate of death within 2 years of surviving a myocardial infarction. Overall, CHD is the leading cause of death in individuals with DM who are >35 years old. Although a significant portion of this increased risk is associated with the presence of well-characterized risk factors for CHD, a significant proportion remains unexplained. Patients with DM, particularly those with type-2 DM, have abnormal plasma lipid and lipoprotein concentrations that are less commonly present in non-diabetics [4-6]. Patients with poorly controlled type-1 DM can also have a dyslipidemic pattern, but, in this review, we will focus on the dyslipidemia seen commonly in patients with type-2 DM. In particular, we will describe the pathophysiology underlying the increase in plasma very low-density lipoprotein triglyceride levels, the reductions in plasma high-density lipoprotein cholesterol levels, and the abnormal, small, dense low-density lipoproteins that are the central components of diabetic dyslipidemia. The dyslipidemia of DM clearly adds significantly to the high risk for CHD in this group, and must be treated aggressively with diet, weight loss and lipid-altering medications. Combinations of lipid-altering medications, particularly statins and fibrates, can markedly change plasma lipid levels, often bringing them all into the normal range.