Dyslipidemia

Introduction

Dyslipidemia is elevated total cholesterol, low-density lipoprotein (LDL) cholesterol, or triglycerides; low high-density lipoprotein (HDL) cholesterol; or a combination of these abnormalities.

CLINICAL PRESENTATION

• Most patients are asymptomatic for many years. Symptomatic patients may complain of chest pain, palpitations, sweating, anxiety, shortness of breath, abdominal pain, or loss of consciousness or difficulty with speech or movement.
• Depending on the lipoprotein abnormality, signs on physical examination may include cutaneous xanthomas, peripheral polyneuropathy, high blood pressure, and increased body mass index or waist size.

DIAGNOSIS

• Measure fasting lipoprotein profile (total cholesterol, LDL, HDL, triglycerides) in all adults 20 years of age or older at least once every 5 years.
• Measure plasma cholesterol, triglyceride, and HDL levels after a 12-hour fast because triglycerides may be elevated in non-fasting individuals; total cholesterol is only modestly affected by fasting.
• Two determinations, 1 to 8 weeks apart are recommended to minimize variability and obtain a reliable baseline. If the total cholesterol is greater than 200 mg/dL (>5.17 mmol/L), a second determination is recommended, and if the values are greater than 30 mg/dL (>0.78 mmol/L) apart, use the average of three values.
• History and physical examination should assess: (1) presence or absence of cardiovascular risk factors or definite cardiovascular disease; (2) family history of premature cardiovascular disease or lipid disorders; (3) presence or absence of secondary causes of dyslipidemia, including concurrent medications; and (4) presence or absence of xanthomas, abdominal pain, or history of pancreatitis, renal or liver disease, peripheral vascular disease, abdominal aortic aneurysm, or cerebral vascular disease (carotid bruits, stroke, or transient ischemic attack).
• Diabetes mellitus and the metabolic syndrome are considered CHD risk equivalents; their presence in patients without known CHD is associated with the same level of risk as patients without them but having confirmed CHD.
• Lipoprotein electrophoresis is sometimes performed to determine which class of lipoproteins is involved. If the triglycerides are less than 400 mg/dL (4.52 mmol/L), and neither type III dyslipidemia nor chylomicrons are detected by electrophoresis, then one can calculate VLDL and LDL concentrations: VLDL = triglycerides ÷ 5; LDL = total cholesterol – (VLDL + HDL). Initial testing uses total cholesterol for case finding, but subsequent management decisions should be based on LDL.

TREATMENT

Goals of Treatment: Lower total and LDL cholesterol to reduce the risk of first or recurrent events such as MI, angina, heart failure, ischemic stroke, or peripheral arterial disease.

NONPHARMACOLOGIC THERAPY

• Begin therapeutic lifestyle changes (TLCs) on the first visit, including dietary therapy, weight reduction, and increased physical activity. Advise overweight patients to lose 10% of body weight. Encourage physical activity of moderate intensity 30 minutes a day for most days of the week. Assist patients with smoking cessation and control of hypertension.
• The objectives of dietary therapy are to progressively decrease intake of total fat, saturated fat, and cholesterol and to achieve a desirable body weight.
• Increased intake of soluble fiber (oat bran, pectins, psyllium) can reduce total and LDL cholesterol by 5% to 20%. However, they have little effect on HDL-C or triglycerides. Fiber products may also be useful in managing constipation associated with bile acid resins (BARs).
• Fish oil supplementation reduces triglycerides and VLDL-C, but it either has no effect on total and LDL-C or may elevate these fractions. Other actions of fish oil may account for any cardioprotective effects.
• Ingestion of 2 to 3 g daily of plant sterols reduces LDL by 6% to 15%. They are usually available in commercial margarines.
• If all recommended dietary changes were instituted, the estimated average reduction in LDL would range from 20% to 30%.

PHARMACOLOGIC THERAPY

Niacin 50, 100, 250, and 500 mg tablets; 125, 250, and 500 mg capsules 0.5–1 g three times daily OR

Lovastatin (Mevacor) 20 and 40 mg tablets 20–40 mg OR

Pravastatin (Pravachol) 10, 20, 40, and 80 mg tablets. 10–20 mg/day OR

Atorvastatin (Lipiget) 10, 20, 40, and 80 mg tablets. 10 mg/day OR

Rosuvastatin (Crescor) 5, 10, 20, and 40 mg tablets. 5 mg 0r 10mg/day at night