8/24 5111 Cholesterol

What is cholesterol?

• A 4-ring molecule

• Precursor to steroid hormones; required for growth, development, and reproduction of mammals

• However, excess levels lead to atherosclerotic cardiovascular disease (ASCVD)

  • Includes cerebrovascular disease, coronary heart disease

How do we get cholesterol?

1. 20-40% from exogenous sources. E.g., diet

   • Primarily found in animal fats and oils

   • Organ meats, egg yolks, dairy fat, shellfish

2. 60-80% from endogenous sources (mostly produced by liver)

Cholesterol in the blood

Cholesterol is packaged into lipoproteins

Lipoproteins have other components, including triglycerides and apolipoproteins

What is a lipid panel?

A standard series of lab tests measuring cholesterol that includes:

• Total cholesterol (TC)

• HDL cholesterol (HDL-c)

• Triglycerides (Trig or TG)

Results will also include calculated values:

• Calculated LDL cholesterol (LDL-c)

• Non-HDL-cholesterol (TC minus HDL-c)

Normal or desirable/ideal levels of cholesterol for the general population (in mg/dL)

1. Total cholesterol: under 200

2. LDL cholesterol: under 100

3. HDL cholesterol: over 40 for men, over 50 for women

4. Triglycerides: under 150

5. Non-HDL-cholesterol: under 130

HDL (high-density lipoprotein) cholesterol

Considered “good” cholesterol because of inverse relationship with ASCVD

• Generally, higher HDL levels are better

HDL returns excess cholesterol back to liver

Non-HDL cholesterol

Defined as total cholesterol minus HDL cholesterol

• Represents all the atherogenic lipoproteins (aka “bad cholesterol”)

• Can be calculated whether blood sample was collected with or without fasting

Current treatment of cholesterol disorders now focuses on both LDL cholesterol and non-HDL cholesterol

What are the types of non-HDL cholesterol?

1. LDL (low density lipoprotein)

2. IDL (intermediate density lipoprotein)

3. VLDL (very low density lipoprotein)

LDL cholesterol

Historically, the main target when treating cholesterol disorders

• LDL has highest concentration of cholesterol among all lipoproteins

Is usually calculated from other parts of the lipid panel

Several mathematical equations/systems are available

• Traditional equation: Friedewald equation

• Newer methods: Martin-Hopkins equation, NIH 2 equation

  • Preferred over Friedewald equation

Triglycerides

Structurally different from cholesterol

Are naturally higher after ingestion of food

• Reason why some patients are instructed to fast before lab test

Also considered atherogenic (contributes to ASCVD)

Levels >500 mg/dL are considered very high

Levels >1000 mg/dL increase risk of pancreatitis

• Painful inflammation of the pancreas, often requiring hospitalization for treatment

Often elevated in patients with diabetes

How many people have high cholesterol?

How often to test for cholesterol?

Screening should start at age 19 and once every 5 years thereafter

• More often in patients at higher risk

Standard non-fasting or fasting lipid panel is recommended

• Fasting: 9-12 hours without food, more accurate calculation of LDL-c

If TG >400 mg/dL with non-fasting lipid panel, then a fasting lipid panel should be performed to more accurately estimate LDL-c level.

Patients taking meds to lower cholesterol will require more frequent testing.

What if a patient’s lipid panel results are higher than ideal?

Consider lifestyle modifications

1. Moderate-to-vigorous intensity physical activity >150 min/week

2. Upper and lower body resistance training 2x/week

3. Weight loss of 5-10% of body weight

4. Diet emphasizing intake of fruit, vegetables, nuts, legumes, whole grains, and fiber

5. Diet that replaces saturated and trans fats with dietary monounsaturated and polyunsaturated fats

6. Smoking cessation

For patients with hypertriglyceridemia, also reduce intake of added sugar, refined carbohydrates, and alcohol.

Who should get treated with meds for high cholesterol?

I.e., statin medications

1. Patients with ASCVD

   • Coronary heart disease (myocardial infarction aka heart attack, chronic chest pain), stroke or transient ischemic attack (TIA), peripheral artery disease

2. Individuals with extremely elevated LDL-c (≥190 mg/dL)

   • Usually caused by genetic factors (e.g. familial hypercholesterolemia)

3. Patients with diabetes

4. Adults 30-79 y/o with elevated predicted risk for ASCVD

   • PREVENT-ASCVD risk calculator

Why is it important to lower cholesterol levels?

Reduces risk of coronary heart disease [myocardial infarction (heart attack), chronic chest pain], stroke, peripheral artery disease, hospitalizations, disability, reduced quality of life, etc.

How are pharmacists involved in treating lipid disorders?

1. Educate patients on disease, lipid-lowering meds, and lifestyle modifications

2. See patients in clinic to make therapy decisions

   • Change/add medications, adjust doses, order follow-up lab tests

3. Make recommendations to other providers regarding drug therapy

4. Take blood samples to measure cholesterol levels