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Home > Patients & Visitors > Diseases & Conditions > Others > High Cholesterol and Lipid

High Cholesterol and Lipid

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Definition

Hyperlipidemia refers to increased levels of lipids (fats) in the blood, including cholesterol and triglycerides. Although hyperlipidemia does not cause a person to feel bad, it can significantly increase the risk of coronary heart disease (CHD). People with CHD develop thickened or hardened arteries in the heart muscle. This can cause chest pain, a heart attack, or both. Because of these risks, treatment is often recommended for people with hyperlipidemia.


This topic reviews the risk factors for coronary heart disease, the types of lipids, and when cholesterol testing should begin.


LIPID TYPES

There are many different types of lipid particles (lipoproteins). Blood tests can determine levels of the most commonly measured lipoproteins. The standard lipid blood tests include a measurement of total cholesterol, LDL and HDL cholesterol, and triglycerides.

 

Total cholesterol - An elevated total cholesterol level is associated with an increased risk of CHD A. desirable total cholesterol level is usually less than 200 mg/dL (5.17 mmol/L). A total cholesterol level of 200 to 239 mg/dL (5.17 to 6.18 mmol/L) is borderline high, while a value greater than or equal to 240 mg/dL (6.21 mmol/L) is high. However, most decisions about treatment are made based upon the level of LDL or HDL cholesterol, rather than the level of total cholesterol.


The total cholesterol can be measured any time of day. It is not necessary to fast (avoid eating for 12 hours) before testing.

 

LDL cholesterol - The low density lipoprotein (LDL) cholesterol (sometimes called bad cholesterol) is a more accurate predictor of CHD than total cholesterol. Higher LDL cholesterol concentrations are associated with an increased incidence of CHD in many studies.


Most healthcare providers prefer to measure LDL cholesterol after the person has fasted (not eaten) for 12 to 14 hours. A test to measure LDL in people who have not fasted is also available, although the results may differ slightly from the fasting result.


People with hyperlipidemia should know their own LDL cholesterol level, as well as their goal LDL. This goal depends upon several factors, including the person's history of CHD or CHD risk equivalents and their 10-year risk score of developing CHD.

Ten year risk of developing CHD - The 10-year risk score is based on information from the Framingham Heart Study, a large study that has followed participants, as well as their children and grandchildren, for greater than 50 years. The 10-year risk can be calculated for women and for men.

 

Triglycerides - High triglyceride levels are also associated with an increased risk of CHD. Triglyceride levels are divided as follows:

  • Normal - less than 150 mg/dL (1.69 mmol/L)
  • Borderline high - 150 to 199 mg/dL (1.69 to 2.25 mmol/L)
  • High - 200 to 499 mg/dL (2.25 to 5.63 mmmol/L)
  • Very high - greater than 500 mg/dL (5.65 mmol/L)


Triglycerides should be measured after fasting for 12 to 14 hours.

 

HDL cholesterol - Not all cholesterol is bad. Elevated levels of HDL cholesterol actually lower the risk of heart disease. In fact, a very high HDL (greater than or equal to 60 mg/dL or 1.55 mmol/L) is considered a negative risk factor for CHD (removes one risk factor). On the other hand, treatment is sometimes recommended for people with low levels of HDL cholesterol (<40 mg/dL or 1.03 mmol/L), particularly if they already have heart disease.


Similar to total cholesterol, the HDL-cholesterol can be measured on any blood specimen. It is not necessary to be fasting.

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High Cholesterol Treatment Options

Lipid levels can be lowered with lifestyle changes, medications, or a combination of these approaches. In certain cases, a clinician will recommend a trial of lifestyle changes before recommending a medication.


Lifestyle changes - All the patients with high LDL cholesterol should try to make some changes in their day-to-day habits, by reducing total and saturated fat in the diet, losing weight (if overweight or obese), performing aerobic exercise, and eating plant stanols/sterols.

The benefits of such lifestyle modifications may be evident within 6 to 12 months. However, the success of lipid lowering with lifestyle modification varies widely, and clinicians may elect to begin drug therapy before this time period is over.

 

Medications - There are many medications available to help lower elevated levels of LDL cholesterol and triglycerides, but only a few for increasing HDL cholesterol. Each category of medication targets a specific lipid and varies in how it works, how effective it is, and how much it costs. Your healthcare provider will recommend a medication or combination of medications based on blood lipid levels and other individual factors.


Statins - Statins are the most powerful drugs for lowering LDL cholesterol and are the most effective drug for prevention of coronary heart disease, heart attack, stroke, and death. Statins include lovastatin, pravastatin, simvastatin, fluvastatin, atorvastatin, and rosuvastatin These medications decrease the body's synthesis of cholesterol and can reduce LDL levels by as much as 20 to 60 percent. In addition, statins can lower triglycerides and slightly raise HDL cholesterol levels.

Statins have fewer side effects than other cholesterol-lowering medications. It is important to closely follow the dosing instructions for when to take statins; some are more effective when taken before bedtime while others should be taken with a meal.

In addition, some foods, such as grapefruit or grapefruit juice, can increase the risk of side effects of statins. Most manufacturers recommend that people who take lovastatin, simvastatin, or atorvastatin consume no more than one-half of a grapefruit or 8 ounces of grapefruit juice per day.

Ezetimibe - Ezetimibe (Zetia®) impairs the body's ability to absorb cholesterol from food as well as cholesterol that the body produces internally. It lowers LDL levels when used alone. It has relatively few side effects when used alone.


However, there are no studies that demonstrate better outcomes in patients who take ezetimibe, either alone or in combination with other cholesterol-lowering medications. Further study is needed before ezetimibe is recommended as a first-line treatment.


Bile acid sequestrants - The bile acid sequestrants include cholestyramine, colestipol, and colesevelam (table 2). These medications bind (combine with) bile acids in the intestine, reducing the amount of cholesterol absorbed from foods.


Bile acid sequestrants may be recommended to treat mild to moderately elevated LDL cholesterol levels. However, side effects can be bothersome, and may include nausea, bloating, cramping, and liver injury. Taking psyllium (a fiber supplement, such as Metamucil®) can sometimes reduce the dose required and the side effects.


Bile acid sequestrants can interact with some medications, including as digoxin (Lanoxin®) and warfarin (Coumadin®), and with the absorption of fat-soluble vitamins (including vitamins A, D, K, and E). Taking these medications at different times of day can solve these problems in some cases.

Nicotinic acid (Niacin) - Nicotinic acid is a vitamin that is available in immediate-release, sustained-release, and extended-release formulations. It lowers levels of both Nicotinic acid may be recommended for people with elevated cholesterol levels and some types of familial hyperlipidemia.


  • Side effects - Nicotinic acidhas several possible side effects, including flushing (when the face or body turns red and becomes warm), itching, nausea, and numbness and tingling. This medication can also injure the liver; patients who use it require regular monitoring of liver function.


Taking nicotinic acid with food and taking aspirin (325 to 650 mg) 30 minutes before can decrease the side effects. Side effects often improve after 7 to 10 days. The immediate-release formulation is more likely to produce side effects, but is also more effective at lowering cholesterol levels and less likely to injure the liver than certain sustained-release formulations. The sustained-release and extended-release formulations have fewer side effects and are usually taken at night with a meal or snack.

Nicotinic acid can produce other side effects in some people, including insulin resistance, which can increase blood glucose levels in diabetics. It can increase uric acid levels in people with gout and is not recommended for this group. Nicotinic acid can also produce low blood pressure in people taking vasodilator medications such as nitroglycerin, and it can sometimes worsen angina pectoris (chest pain).


Fibrates - Fibrate medications (gemfibrozil, fenofibrate and fenofibric acid) can lower triglyceride levels and raise HDL cholesterol levels.

Fibrates may be recommended for people with elevated triglyceride levels and hyperlipidemia. Fibrates have been associated with muscle toxicity (causing muscle pain or weakness), especially when used by people with kidney insufficiency or when used in combination with a statin medication. Fenofibrate/fenofibric acid (Tricor®, Triglide®, Trilipex®) are less likely to interact with statins than gemfibrozil, and are safer in people who must use both medications.

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Treatment and drugs

The decision to start lipid-lowering treatment is made on a case-by-case basis. Clinicians consider current lipid levels, the presence or absence of CHD, and other risk factors for CHD.

People with CHD - Several large trials have demonstrated that aggressive lipid lowering is beneficial in people with CHD.


  • A target LDL cholesterol level below 70 to 80 mg/dL (1.81 to 2.07 mmol/L) is recommended for people who have CHD and have multiple major risk factors (eg, people with diabetes or who smoke). Some providers treat all very high risk patients with a statin, no matter what their LDL level.
  • People who have a heart attack (myocardial infarction or MI) are started on cholesterol-lowering medication while in the hospital and are advised to make lifestyle changes, regardless of their LDL level.
  • A target LDL cholesterol level less than 100 mg/dL (2.59 mmol/L) is recommended for people who have CHD but do not have many additional risk factors. Lifestyle changes as well as medications may be recommended when LDL cholesterol levels are greater than 100 mg/dL (2.59 mmol/L).


These general guidelines may be modified by other individual factors.

 

People without CHD - People without a history of CHD also appear to benefit from lipid lowering therapy, although the treatments are not as aggressive as in patients with CHD. Guidelines from the United States National Cholesterol Education Program make the following recommendations:

  • A target LDL cholesterol less than 130 mg/dL (3.36 mmol/L) is recommended for people with two or more risk factors for CHD and a 10-year risk of CHD between 10 and 20 percent. The 10-year risk can be calculated for women and for men. Lifestyle changes AND medication are generally recommended when the LDL cholesterol is above 130 mg/dL (3.36 mmol/L).
  • A target LDL cholesterol less than 130 mg/dL (3.36 mmol/L) is recommended for patients with two or more risk factors for CHD and a 10-year risk of CHD less than 10 percent. The 10-year risk can be calculated for women and for men. Lifestyle changes are generally recommended when the LDL cholesterol is above 130 mg/dL, although medication is not generally recommended until levels are above 160 mg/dL (4.14 mmol/L).
  • A target LDL cholesterol less than 160 mg/dL (4.14 mmol/L) is recommended for patients with zero to one risk factor for CHD. Lifestyle changes are generally recommended when the LDL cholesterol level is above 160 mg/dL, although medication is not generally recommended until levels are above 190 mg/dL (4.91 mmol/L).


Other experts make alternative recommendations, including global risk-based approaches to therapy.

 

Other special groups


Hypertriglyceridemia
 - High triglycerides have not generally been thought to pose the same risk of CHD as LDL cholesterol. However, healthcare providers often recommend treatment for people with elevated triglyceride levels if they:

  • Have very high levels (>500 mg/dL or 5.65 mmol/L)
  • Also have high LDL cholesterol or low HDL cholesterol levels
  • Have a strong family history of CHD
  • Have other risk factors for CHD

 

Diabetes mellitus - People with diabetes (type 1 or 2) are at high risk of heart disease. Thus, an LDL level below 100 mg/dL (2.59 mmol/L) is recommended in people with diabetes.

 

Elderly - The decision to treat high cholesterol levels in an elderly person depends upon the individual's chronologic age (age in years) and physiologic age (health, fitness). A person with a limited life span and underlying illness is probably not a good candidate for drug therapy. On the other hand, an otherwise healthy elderly person should not be denied drug therapy simply on the basis of age alone. In general, the treatment goals discussed above are followed for elderly people.

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