The link between triglycerides and CHD is complex and may be explained by the association of high triglycerides, low HDL-cholesterol and unusually atherogenic LDL-cholesterol. Elevated triglycerides also often reflect an increase in triglyceride-rich remnant lipoproteins that have atherogenic potential. Patients with primarily triglyceride elevation and normal or moderately elevated cholesterol are candidates for treatment if there is evidence of cholesterol-rich VLDL and IDL particles, typically found in patients with triglyceride levels between 200 and 499 mg/dL and occasionally between 500 and 1,000 mg/dL. If triglycerides are greater than 500, triglyceride-lowering drugs become first-line therapy. The clinician may wish to consider the use of statin therapy. This is especially true if there is a strong family history of CHD and dyslipidemia, such as familial combined hyperlipidemia, or if the patient has evidence of atherosclerotic disease. Treatment can also be supported in diabetics with or without low HDL-cholesterol. Patients with very high triglycerides (greater than 1,000 mg/dL) are at increased risk of hepatomegaly, splenomegaly, hepatic steatosis and pancreatitis and are candidates for dietary and drug therapy. Patients with fasting triglycerides less than 1,000 mg/dL are at less immediate risk of pancreatitis. After ruling out or controlling for secondary causes (e.g., diabetes mellitus, hypothyroidism, chronic renal failure, alcohol abuse, hormone replacement therapy and/or oral contraceptives), the National Institutes of Health recommend dietary measures for initial management of borderline and high triglycerides (please see Appendix B, "Identified Secondary Causes and Conditions Associated with Hyperlipidemia," for additional secondary causes). If dietary and lifestyle modification (weight reduction if needed, decrease in alcohol, increase physical activity, smoking cessation) does not lower triglycerides to desired level, then drug therapy is indicated. (See Appendix A, "Omega-3 Fatty Acids," and Appendix C, "Drug Companion Document.") Uncontrolled glucose levels in patients with diabetes mellitus contribute to hypertriglyceridemia. Glucose levels in patients with diabetes should be under control to bring triglyceride levels under control. When triglycerides are over 400 mg/dL, the LDL-cholesterol cannot be calculated and a direct measure of LDL, where available, is preferred. Although the LDL-cholesterol can be calculated when the triglycerides are moderately elevated (200-400 mg/dL), keep in mind that the LDL-cholesterol may be underestimated due to the Friedenwald equation. LDL-cholesterol = Total cholesterol minus HDL-cholesterol minus (triglyceride divided by 5). Non-HDL-cholesterol becomes a secondary target when triglycerides are 200-499. The non-HDL target is 30 mg/dL higher than the LDL target. Non-HDL-cholesterol is calculated by the formula non-HDL- cholesterol = T-cholesterol minus HDL-cholesterol. (Grundy, 1998 [R]; McKenney, 2001b [R]; National Cholesterol Education Program, 2001 [R]) |