Clinical significance of plasma lipid levels

Abstract

Epidemiologic studies have established that elevated low-density lipoprotein (LDL) cholesterol values and decreased levels of high-density lipoprotein (HDL) cholesterol are risk factors for coronary artery disease (CAD). Results from clinical trials indicate that reduction in LDL cholesterol decreases the incidence of and reduces the risk of CAD.

The National Cholesterol Education Program recently developed guidelines for the evaluation of plasma cholesterol in adults. Initial classification is categorized and based on the following values: <200 mg/dl is “desirable” blood cholesterol; from 200 through 239 mg/dl is classified as “moderate-high” blood cholesterol; and ≥240 mg/dl is “high” blood cholesterol. Decision-making regarding therapeutic intervention is influenced by the presence of other lipoprotein risk factors, such as reduced HDL cholesterol and elevated lipoprotein (a), and nonlipid factors, including age, sex, hypertension, obesity, smoking, diabetes mellitus, and family or patient history of CAD. Persons with borderline-high blood cholesterol and established CAD or 2 other risk factors as well as those with high blood cholesterol should undergo lipoprotein analysis.

LDL cholesterol is the primary lipoprotein to consider when determining treatment goals. Patients with LDL cholesterol levels >160 mg/dl without CAD or 2 other risk factors and those patients with LDL cholesterol >130 mg/dl with CAD or 2 other risk factors are initially managed with dietary therapy. The goal of treatment of hyperlipidemia is to reduce LDL cholesterol to <160 mg/dl or to <130 mg/dl in patients with established CAD or with 2 other risk factors. Dietary therapy follows the American Heart Association and National Cholesterol Education Program's Step-One and Step-Two Diets. When it is necessary to institute a pharmacologic regimen, medication is administered as an adjunct to diet.