The LDL level is normal or increased. Fasting chylomicronemia results when there is a coexisting primary or secondary form of hypertriglyceridemia. VLDL and chylomicrons compete for binding to lipoprotein lipase, and both lipoproteins may accumulate. A low HDL level results from impaired lipolysis of triglyceride-rich lipoproteins, which supply components for HDL synthesis. In diabetics with persistent hypertriglyceridemia, gemfibrozil is suitable because it enhances the activity of lipoprotein lipase and possibly reduces the secretion of VLDL from the liver.
Statins are also effective for the dyslipidemia of diabetes.
Hypothyroidism causes severe elevation of LDL because of reduced LDL receptor activity and frequently causes hypertriglyceridemia with an associated reduction in the HDL level as a result of reduced lipoprotein lipase activity. Remnants of chylomicrons and VLDL may also accumulate and unmask type III dysbetalipoproteinemia. The dyslipoproteinemia of hypothyroidism is corrected by thyroid hormone replacement. Patients with nephrotic syndrome are at increased risk for coronary artery disease because of hypercholesterolemia, and the lipid disorder should be treated aggressively if the patient's prognosis is otherwise good. Dietary change, weight loss, and exercise may improve lipoprotein levels, but pharmacological therapy is necessary to achieve desirable levels.