Contemporary recommendations for evaluating and treating hyperlipidemia.

The biochemistry, etiology, and evaluation of hyperlipidemia and its management, including dietary and drug therapies, are discussed. Strong evidence supports the role of increased cholesterol concentrations as an independent risk factor for coronary artery disease (CAD); however, evidence that elevated triglyceride concentrations are also an independent risk factor remains questionable. The cornerstone of the laboratory diagnosis of hyperlipidemia involves repeated measurement of serum or plasma cholesterol and triglyceride concentrations. The goals of therapy should be to reduce cholesterol or triglyceride concentrations or both to below the 75th percentile, modify co-existing risk factors, individualize the treatment, and minimize any adverse effects. Specific interventions must be determined on the basis of patient age, gender, etiology of hyperlipidemia, presence of other risk factors, and degree of lipid abnormality. The majority of patients may be managed with dietary therapy alone. The three-phase diet developed by the American Heart Association emphasizes a gradual reduction in cholesterol and fats with the substitution of polyunsaturated for saturated fats. Patients at risk for CAD with sustained elevations in plasma cholesterol concentrations above the 95th percentile or a triglyceride concentration above 500 mg/dL after an adequate dietary trial should be considered for drug therapy. The effects of cholestyramine and colestipol hydrochloride, niacin, dextrothyroxine, clofibrate, neomycin sulfate, probucol, gemfibrozil, and mevinolin and compactin on lipids and lipoproteins are reviewed. Hyperlipidemia should be managed systematically using information about the association between increased lipid concentrations and CAD, patient risk factors, and limitations of both diet and drug therapy.