What Is Mixed Hyperlipidemia?

Mixed hyperlipidemia is a condition characterized by elevated levels of fats in the blood, including low-density lipoprotein (LDL) cholesterol ("bad" cholesterol) and triglycerides. Because of this, it can increase the risk of heart disease and lead to problems like heart attacks.

Mixed hyperlipidemia can be passed down through families, which is why it's also called familial combined hyperlipidemia. However, it can also be idiopathic (with an unknown cause) or a result of other conditions, such as liver disease, kidney disease, and thyroid disease.

People with mixed hyperlipidemia may develop high cholesterol or high triglyceride levels as teenagers. The condition may also be diagnosed when people are in their 20s and 30s. The levels remain high throughout life. 

Symptoms of Mixed Hyperlipidemia

In the early years, people with mixed hyperlipidemia may have no symptoms. When symptoms do appear, they can include:

• Chest pain
• Cramping of one or both calves when walking
• Sores on the toes that do not heal
• Sudden stroke-like symptoms, such as trouble speaking, drooping on one side of the face, weakness of an arm or leg, and loss of balance

Causes

A number of genes and genetic mutations have been linked to mixed hyperlipidemia, but the exact mutation or cause is still uncertain. Newer studies have suggested there may be a miscommunication between the genes that regulate cholesterol, specifically in what's known as Wnt–LRP6 coreceptor signaling.

Additional Risk Factors

Studies have shown that mixed hyperlipidemia is more common in people who have the following conditions:

• Obesity (being extremely overweight)
• Insulin resistance (when cells in your muscles, fat, and liver don't respond well to the hormone insulin)
• Type 2 diabetes (an impairment in the way the body uses sugar for fuel)
• Hypertension (high blood pressure)
• Nonalcoholic fatty liver disease (liver conditions not caused by overdrinking alcohol)
• Metabolic syndrome (a group of conditions that can lead to heart disease, stroke, or type 2 diabetes)
• Hypothyroidism (an underactive thyroid)
• Alcoholism 

Diagnosis

Mixed hyperlipidemia is diagnosed mainly through blood tests and a physical exam. A lipid panel and other blood tests will measure cholesterol levels in your blood. The tests are done with a small sample of blood taken from one of your veins. The sample is usually collected in the morning, after at least 12 hours of fasting.

Hyperlipidemia is diagnosed if your blood tests reveal:

• Increased LDL cholesterol
• Decreased HDL cholesterol (high-density lipoprotein cholesterol, the "good" cholesterol)
• Increased triglycerides
• Increased total cholesterol

Normal ranges of each of these substances are:

• HDL cholesterol: 40–50 milligrams per deciliter or more
• LDL cholesterol: Less than 100 milligrams per deciliter
• Triglycerides: Less than 150 milligrams per deciliter
• Total cholesterol: 125–200 milligrams per deciliter

Testing for Mixed Hyperlipidemia

Mixed hyperlipidemia may be overlooked without taking a thorough family history or performing additional tests. Tests can tell you whether you have elevated levels of a particular protein in LDL cholesterol called apolipoprotein B100. This protein is responsible for moving cholesterol throughout your body. High levels of it may indicate mixed hyperlipidemia.

Treatment

Generally, mixed hyperlipidemia is treated the same way as nongenetic forms of hyperlipidemia. In most cases, this means a combination of lifestyle changes and medications.

The goal of treatment is to prevent the condition from progressing to atherosclerosis, a buildup of fats, cholesterol, and other substances on artery walls.

Lifestyle Changes

Making changes to your diet is usually the first step your healthcare provider will take to help lower your cholesterol levels. You will need to try dietary changes for several months before your doctor recommends medications. 

Lifestyle changes that can prevent mixed hyperlipidemia include:

• Reducing your intake of foods that contain a lot of saturated fat and sugar
• Eating less beef, chicken, pork, and lamb
• Choosing low-fat dairy products
• Limiting the amount of egg yolks and organ meats like liver that you eat
• Choosing fresh fruits and vegetables
• Avoiding prepackaged cookies and baked goods that contain trans fats

Medication

Medications that can help lower cholesterol levels include statins and fibrates. Common examples of statins prescribed for mixed hyperlipidemia include:

• Mevacor (lovastatin)
• Pravachol (pravastatin)
• Zocor (simvastatin)
• Lescol (fluvastatin)
• Lipitor (atorvastatin)
• Crestor (rosuvastatin)
• Livalo (pitavastatin)

Other medications that can help further lower cholesterol levels may also be prescribed, including:

• Bile acid-sequestering resins
• Ezetimibe
• Nicotinic acids
• PCSK9 inhibitors like Praluent (alirocumab) and Repatha (evolocumab)

Prognosis

Early recognition and healthy lifestyle changes can help you keep mixed hyperlipidemia from progressing to atherosclerosis.

Your overall prognosis will depend on:

• How soon you are diagnosed
• When you start treatment and make the necessary lifestyle changes
• How well you stick to your treatment plan

Possible Complications

Complications from mixed hyperlipidemia arise when the high levels of cholesterol in your blood begin to collect in your arteries and impair your blood flow.

Atherosclerosis and other vascular diseases caused by high cholesterol levels increase your risk of heart attack and stroke.

Summary

Mixed hyperlipidemia is a condition characterized by high cholesterol levels. Symptoms don't usually appear until later in life. When symptoms do arise, you will need medications and lifestyle changes to manage your cholesterol levels and prevent complications, such as heart disease and stroke. With the right interventions, people can keep this condition under control.

A Word From Verywell

There are many things that can cause you to have high levels of cholesterol in your blood, some of which you have control over like your diet choices. Sometimes, though, high cholesterol can be caused by genetic mutations passed on through families or as a complication of other illnesses.

If you have mixed hyperlipidemia, you can still make dietary choices that can help lower your cholesterol. You may also need to take medications. The goal is to prevent the formation of plaques that could lead to atherosclerosis and eventually heart attack or stroke.

Make sure to talk with your doctor not just about your personal lifestyle choices and medical history but your family medical history, as well. Caught early and treated, this condition can minimize its impact on your life.