AssessmentsHypercholesterolemia: Clinical practice
USMLE® Step 1 style questions USMLE
USMLE® Step 2 style questions USMLE
A 65-year-old man comes to the office because of pain in the lower extremities. The pain is associated with walking and relieved by rest. He has a history of myocardial infarction, hypertension, hyperlipidemia, diabetes mellitus, and smoking. Examination of the legs shows atrophic changes with diminished pedal pulses. Which of the following is the most appropriate initial treatment?
Content Reviewers:Rishi Desai, MD, MPH
Most of that recycling happens in the intestines and is facilitated by bile acids which help us reabsorb cholesterol and bring it back into the bloodstream.
There are two main types of cholesterol: HDL or High Density Lipoprotein which is sometimes called “good cholesterol”, and LDL or Low Density Lipoprotein which is sometimes called “bad cholesterol”. But good and bad is overly simplistic, and like all things - the subtleties matter.
LDL is produced by the liver and it carries cholesterol out to the rest of the body.
Now, what makes LDL bad and HDL good is that, whenever there’s a high blood concentration of LDL, the LDL can be ingested by macrophages that sit along vessel walls, forming atherosclerotic plaques.
A diagnosis of hypercholesterolemia requires measuring total cholesterol, LDL cholesterol, HDL cholesterol, and triglycerides.
Cholesterol is measured either as milligrams per deciliter (mg/dL) or millimoles per liter of blood (mmol/L), and it’s recommended to test cholesterol every five years for people aged 20 years or older.
The HDL level should be above 60 mg/dL or 1.55 mmol/L, and the LDL level should be below 130 mg/dL or 3.3 mmol/L in most individuals, or below 70 mg/dL or 1.8 mmol/L in people who have previously had a cardiovascular event.
And of the three - total cholesterol, LDL, and HDL - the LDL is the most relevant indicator of risk.
And having elevated triglycerides is specifically termed hypertriglyceridemia, rather than hypercholesterolemia.
Now, first off, individuals with hypercholesterolemia should make lifestyle modifications, such as exercise and weight loss to achieve a healthy BMI between 18.5 and 25, avoid cigarettes and tobacco products, and reduce consumption of saturated fats, so eating fewer animal products like meat and dairy.
Usually, individuals with a very elevated LDL or with a combination of a moderately elevated LDL and other risk factors for cardiovascular disease are prescribed lipid-lowering medications.
Common risk factors for cardiovascular disease include being a man over the age of 45 or a woman over the age of 50 with HDL cholesterol less than 40 mg/dL or 1 mmol/L, having diabetes, hypertension, a family history of coronary artery disease and hypercholesterolemia, and cigarette smoking.
To be more specific, individuals with an LDL above 190 mg/dL or 4.9 mmol/L, or those with an LDL above 160 mg/dL or 4.1 mmol/L with two or more additional risk factors are started on medication.
Treatment is also started in individuals with an LDL above 130 mg/dL or 3.4 mmol/L with asymptomatic coronary artery disease, as well as individuals above 70 mg/dL or 1.8 mmol/L who have previously had a cardiovascular event.
The first option are statins and they’re generally the first choice in most situations - they lower LDL and triglycerides, and mildly raise the HDL.
LDL is usually measured six weeks after starting statin therapy to see if there’s a response and then done every 6 to 12 months thereafter.
The goal is to get the LDL below 100 mg/dL or 2.6 mmol/L.
On the other hand, for patients with a previous cardiovascular event, lifelong high dose statin therapy with 40 to 80 mg of atorvastatin or 20 to 40 mg of rosuvastatin is used regardless of baseline LDL levels.