In 2004, guidelines for the treatment of hyperlipidemia were updated, and called for consideration of more stringent control of lipids, especially LDL-C (low-density lipoprotein) and HDL-C (high-density lipoprotein), to reduce cardiovascular disease risk. The guidelines are published by the Coordinating Committee of the National Cholesterol Education Program (NCEP) and are endorsed by the National Heart, Lung, and Blood Institute (NHLBI), the American College of Cardiology (ACC), and the American Heart Association (AHA). The complete guidelines can be found on Web sites maintained by the National Institutes of Health (NIH) and ACC. The original condensed guideline is NIH Publication No. 01-3670, published in May 2001. The updated changes for 2004 can be found on the ACC Web site at http://www.circulationaha.org, volume 110, page 227-page 239.
The guidelines delineate the population into one of five coronary heart disease (CHD) risk categories, ranging from lower risk to very high risk (see Table: "CHD Risk Categories and Treatment Options"). Coronary heart disease is defined as a history of myocardial infarction, unstable angina, stable angina, previous coronary artery disease interventions, or evidence of clinically significant myocardial ischemia. 1 Coronary heart disease risk equivalents include peripheral arterial disease, abdominal aortic aneurysm, carotid disease, diabetes, and two or more risk factors with a 10-year risk for CHD of > 20%. 1 The CHD 10-year risk calculation can be determined online using the 10-year risk calculator found at http://www.nhlbi.nih.gov/guidelines/cholesterol (see Table: "CHD 10-Year Risk Calculation"). Risk factors include smoking, hypertension, low HDL-C, family history of premature CHD, and advancing age. Premature is defined as being younger than the definition of "age," which is 45 years or older in men and 55 years or older in women. Other severe risk factors include continued smoking, high triglycerides (> 200 mg/dL) plus elevated non-HDL-C (> 160 mg/dL), metabolic syndrome, and/or emerging risk factors such as highly sensitive C-reactive protein (HS C-RP) > 3 mg/dL or coronary calcium > 75th percentile for age and sex. 1
Major Recommendations
The five major recommended changes to the original guidelines are as follows and are based on lowering the LDL-C as the primary target of treatment; for every 1% reduction in LDL-C an approximate 1% decrease in major CHD events results. 1,2
There are some previous lipid profile parameters that should be considered:
* LDL-C < 70 mg/dL for very high-risk category (previously was 100 mg/dL)
* Begin pharmacological treatment when LDL-C > 100 mg/dL for very high-risk category (previously was 130 mg/dL)
* LDL-C < 130 mg/dL or optional <100 mg/dL for moderately high-risk category (previously was 130 mg/dL). New recommendations also state that pharmacological therapy can begin if LDL-C is 100 to 129 mg/dL.
* Goal of pharmacological therapy is to decrease LDL-C by 30% to 40%, which seems to equate with a reduction of CVD by 30% to 40%.
* Lifestyle changes should be initiated in all people in the moderate to high risk categories regardless of LDL-C levels (previously it was suggested to institute lifestyle changes only in those patients with increased LDL-C levels).
Other recommendations include more aggressive treatment for hyperlipidemia in diabetic patients, and to use the lipid profile rather than cholesterol as a screening tool, monitor triglycerides more closely to increase the recommended level of HDL-C, and obtain, at a minimum, a lipid profile at least every 5 years after the age of 20. Therapeutic lifestyle changes should be recommended, including nutrition, exercise, and weight management. Increased awareness of metabolic syndrome is also emphasized because these patients are at increased risk for developing CVD due to the increase in insulin resistance and hypertension. Hormone replacement therapy (HRT) should not be used to improve the lipid profile. 1
Based on the stricter control of LDL-C, polypharmacy may be the norm when it comes to reducing LDL-C levels. The statins are currently the mainstay of lipid management, but can only achieve target LDL-C levels in 75% of patients when used alone. Current goals with statin use are to lower the LDL-C by a minimum of 30% to 40%. For each doubling of a statin dose, the LDL-C will decrease by approximately 6%.
Combination therapy with a bile acid sequestrant, niacin, ezetimibe, or fibrates can achieve an additional 10% to 20% reduction in LDL-C levels. It should be noted that even with combination therapy, the target of < 70 mg/dL for very high-risk patients may be difficult to achieve if starting LDL-C levels were > 150 mg/dL. 1 Combination therapy is also recommended when triglycerides are high or HDL-C levels are low. 4
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