Dyslipidemia resident survival guide
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief:
Overview
Classification
There are several ways in which lipoprotein abnormalities are classified. Lipoprotein disorders can be classified according to:
- The pattern of change in the lipoprotein levels, described as hyperlipidemia (increase in lipid levels) and hypolipidemia (decrease in lipid levels): However, this classification is problematic because the lipids and lipoproteins levels in some situation can be elevated in some types of lipoproteins and lipids and decreased in others.
- Phenotype, or the specific type of lipid that is increased, as classified by Fredrickson: This classification is problematic because it does not include abnormalities in the level of HDL.
- Etiology, as primary (genetic) or secondary to another condition: This classification can be problematic, because most conditions involve the intersection of genetics and lifestyle issues. However, there are a few well defined genetic conditions that are usually easy to identify.
- Levels of measured lipids (cholesterol and triglycerides), described as hypercholesterolemia and hypocholesterolemia or hypertriglyceridimia and hypotriglyceridemia: This distinction is not specific because it does not reflect the specific lipoprotein(s) that are abnormally high or low.
Fredrickson Classification of Hyperlipoproteinemia
Hyperlipoproteinemia | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Type I: Familial hyperchylomicronemia | Type II | Type III: Dysbetalipoproteinemia | Type IV: Primary hypertriglyceridemia | Type V: Mixed hyperlipoproteinemia | |||||||||||||||||||||||||||||||||||||||||||||||||||
Type A: Familial hypercholesterolemia | Type B: Familial combined hyperlipidemia | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Type A | Type B | Type C | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Hyperlipoproteinemia | Synonyms | Problems | Labs description | Treatment |
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Type I | Buerger-Gruetz syndrome, primary hyperlipoproteinaemia, or familial hyperchylomicronemia | Decreased lipoprotein lipase (LPL) or altered ApoC2 | Elevated chylomicrons | Diet control |
Type IIa | Polygenic hypercholesterolaemia or familial hypercholesterolemia | LDL receptor deficiency | Elevated LDL only | Bile acid sequestrants, statins, niacin |
Type IIb | Combined hyperlipidemia | Decreased LDL receptor and increased ApoB | Elevated LDL, VLDL and triglycerides | Statins, niacin, gemfibrozil |
Type III | Familial Dysbetalipoproteinemia | Defect in ApoE synthesis | Increased IDL | Drug of choice: Gemfibrozil |
Type IV | Endogenous Hyperlipemia | Increased VLDL production and decreased elimination | Increased VLDL | Drug of choice: Niacin |
Type V | Familial Hypertriglyceridemia | Increased VLDL production and decreased LPL | Increased VLDL and chylomicrons | Niacin, gemfibrozil |
Unclassified forms
Non-classified forms are extremely rare:
- Hypo-alpha lipoproteinemia
- Hypo-beta lipoproteinemia (prevalence 0.01-0.1%)
Classification According to Etiology
Lipoprotein Disorders | |||||||||||||||||||||||||||||||||||||||||||||||||||
Primary (Genetic) | Secondary | ||||||||||||||||||||||||||||||||||||||||||||||||||
LDL | Chylomicron Remnants | Lipoproteins Rich in Triglyceride (Chylomicrons, VLDL, IDL) | HDL | Multiple lipoproteins | Alcohol Diabetes Drugs Liver disease Obesity Renal disease Smoking Thyroid | ||||||||||||||||||||||||||||||||||||||||||||||
High LDL: -Familial hypercholesterolemia -Familial defective apo B 100 -Autosomal dominant hypercholesterolemia (PCSK9) -Autosomal recessive hypercholesterolemia -Familial sistosterolemia -Familial lipoprotein a lipoproteinemia Low LDL: -Abetalipoproteinemia -Hypobetalipoproteinemia -PCSK 9 deficiency | -Deficiency in hepatic lipase -Type III dysbetalipoproteinemia | -Deficiency in lipoprotein lipase -Deficiency in Apo C-II -Deficiency in Apo A-V -Familial combined hyperlipidemia -Familial hypertriglyceridemia - Chylomicron retention disease | High LDL: -Cholesteryl ester transferase protein deficiency Low HDL: -Deficiency in Apo A-I -Deficiency in lecithin cholesterol acyltransferase (LCAT) -Familial hypoalphalipoproteinemia -Nieman-Pick disease -Tangier disease | - Familial combined hypolipidemia (ANGPTL3) | |||||||||||||||||||||||||||||||||||||||||||||||
Classification According to Laboratory Results
Lipid Laboratory Tests | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Total cholesterol | LDL-C | HDL-C | Triglycerides | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
High total cholesterol | Low total cholesterol | High LDL | Low LDL | High HDL | Low HDL | High triglyceride | Low triglyceride | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Causes
Secondary causes of dyslipidemia may cause either an increase in total-cholesterol & low density lipoprotein-cholesterol (LDL-C) or an increase in total triglycerides & very low density lipoprotein cholesterol (VLDL-C). Common causes are listed below.
Increase in Total Cholesterol and LDL-C
- Hypothyroidism
- Nephrosis
- Dysgammaglobulinemia (systemic lupus erythematosus, multiple myeloma)
- Cholestatic hepatic diseases due to abnormal lipoproteins (e.g. primary biliary cirrhosis)
- Administration of protease inhibitors (treatment for HIV infection)
- Administration of progestin or anabolic steroids
Increase in Total Triglycerides and VLDL-C
- Chronic kidney disease
- Type 2 diabetes mellitus
- Obesity
- Excessive alcohol intake
- Hypothyroidism
- Administration of anti-hypertensive therapy (thiazide diuretics or B-blockers)
- Administration of corticosteroids
- Severe stress that increases endogenous corticosteroid concentration
- Elevated concentrations of estrogen (administration of oral (not transdermal) estrogen therapy, oral contraceptives, or pregnancy)
- Administration of protease inhibitors (treatment for HIV infection)
To view a comprehensive list of dyslipidemia causes, click here
Screening
Abbreviations: ASA: American society of anesthesiologists; BP: Blood Pressure; CCS: Canadian cardiovascular society; CrCl: Creatinine clearance; CXR: Chest X-ray; DNI: Do not intubate; DNR: Do not resuscitate; ECG: Electrocardiogram; eGFR: estimated glomerular filtration rate; HR:Heart rate; INR: International normalized ratio; LMWH: Low molecular weight heparin; LV: Left ventricle; LVED: Left ventricular ejection fraction; NOAC: Novel oral anticoagulant; NPO: Nothing per os; PMI: Point of maximal impulse; PT: Prothrombin time; RR: Respiratory rate; SpO2: Oxygen saturation; T: Temperature; VT: Ventricular tachycardia
Identify risk factors for CAD Major risk factors: ❑ Advanced age ❑ ↑ total serum cholesterol ❑ ↑ non-HDL-C (calculated by: total cholesterol minus HDL-C) ❑ ↑ LDL-C (either measured or calculated by: total cholesterol minus HDL-c minus (total triglycerides/5)) ❑ ↓ HDL-C ❑ Diabetes mellitus ❑ Hypertension ❑ Cigarette smoking ❑ Family history of CAD ❑ Obesity, especially abdominal ❑ Family history of hyperlipidemia ❑ Small, dense LDL-C ❑ ↑ Apo-B ❑ ↑ LDL particle number (measured by ApoB) ❑ Fasting/postprandial hypertriglyceridemia ❑ Polycystic ovarian syndrome ❑ Dyslipidemic triad ❑ ↑ lipoprotein ❑ ↑ clotting factors ❑ Inflamamtory markers (e.g. hsCRP or Lipoprotein-associated phospholipase A2 (Lp-PLA2) ❑ Hyperhomocysteinemia ❑ ApoE4 isoform | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
High (Framingham 10-year global risk > 20%) | Intermediate (Framingham 10-year global risk between 10% and 20%) | Lower (Framingham 10-year global risk < 10%) | Optimal (Framingham 10-year global risk < 10% with optimal levels or risk factors and heart-healthy lifestyle) | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Does the patient have type 2 diabetes mellitus? | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Yes | No | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Does the patient have ALL the following criteria for low-risk dyslipidemia during previous work-up? ❑ Low LDL-C < 100 mg/dL, AND ❑ HDL-C > 50 mg/dL, AND | Adult patient | Pediatric patient (age at least 2 years) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Yes. The patient has ALL of the criteria for low-risk dyslipidemia | Either unknown history of lipid profile or No, the patient does not have ALL of the criteria for low-risk dyslipidemia (at least 1 criterion is not met) | Does that patient have risk factors for CAD (listed above)? | Does the patient have risk factors for CAD (listed above)? | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Screen every 2 years | Screen annually | No | Yes | Yes | No | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Screen patient more frequently than patients with no risk factors based on clinical judgement (unknown optimal interval) | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Male patient | Female patient | Screen every 3 to 5 years | Do not screen patient for dyslipidemia | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Age between 20 and 45 years | Age > 45 years to 65 years | Age > 65 years | Age between 20 years and 55 years | Age > 55 years to 65 years | Age > 65 years | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Screen every 5 years More frequent screening is recommended for patients with risk factors for CAD (shown above) | Screen every 1 to 2 years More frequent screening is recommended for patients with risk factors for CAD (shown above) | Screen annually | Screen every 5 years More frequent screening is recommended for patients with risk factors for CAD (shown above) | Screen every 1 to 2 years More frequent screening is recommended for patients with risk factors for CAD (shown above) | Screen annually | ||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Complete Diagnostic Approach
Boxes in red signify that an urgent management is needed.
Abbreviations: ASA: American society of anesthesiologists; BP: Blood Pressure; CCS: Canadian cardiovascular society; CrCl: Creatinine clearance; CXR: Chest X-ray; DNI: Do not intubate; DNR: Do not resuscitate; ECG: Electrocardiogram; eGFR: estimated glomerular filtration rate; HR:Heart rate; INR: International normalized ratio; LMWH: Low molecular weight heparin; LV: Left ventricle; LVED: Left ventricular ejection fraction; NOAC: Novel oral anticoagulant; NPO: Nothing per os; PMI: Point of maximal impulse; PT: Prothrombin time; RR: Respiratory rate; SpO2: Oxygen saturation; T: Temperature; VT: Ventricular tachycardia
Obtain a Detailed History History of present illness ❑ Address specific patient symptoms and complaints ❑ Obtain review of systems relevant to dyslipidemia and diseases associated with dyslipidemia
❑ Intake of dietary fat, saturated fat, fiber, and cholesterol intake ❑ Exercise patterns ❑ History of alcohol use ❑ History of smoking ❑ History of CAD or myocardial infarction ❑ History of diabetes mellitus ❑ History of hypertension ❑ History of renal disease ❑ History of hepatic disease ❑ History of stroke (ischemic or hemorrhagic) or transient ischemic attack (TIA) ❑ History of hypothyroidism Medications ❑ Current prescribed medications ❑ List of over-the-counter drugs ❑ Previous intake of medications and reason for discontinuation ❑ History of drug adverse effects ❑ History of herbs and supplement use ❑ Compliance to medications Allergies ❑ Known drug allergies ❑ Known environmental/food allergies ❑ Family history of premature CAD (i.e. Established CAD in father or 1st degree male relative before the age of 55 years OR established CAD in mother or 1st degree female relative before the age of 65 years) ❑ Family history of hypothyroidism ❑ Family history of stroke/TIA ❑ Family history of peripheral vascular disease ❑ Occupation ❑ Exercise ❑ Diet (general) ❑ Smoking history ❑ Alcohol use ❑ Recreational drug use ❑ Stress ❑ Sexual lifestyle & contraceptive methods | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Assess for CAD Risk Factors Major risk factors: ❑ Advanced age ❑ ↑ total serum cholesterol ❑ ↑ non-HDL-C (calculated by: total cholesterol minus HDL-C) ❑ ↑ LDL-C (either measured or calculated by: total cholesterol minus HDL-c minus (total triglycerides/5)) ❑ ↓ HDL-C ❑ Diabetes mellitus ❑ Hypertension ❑ Cigarette smoking ❑ Family history of CAD ❑ Obesity, especially abdominal ❑ Family history of hyperlipidemia ❑ Small, dense LDL-C ❑ ↑ Apo-B ❑ ↑ LDL particle number (measured by ApoB) ❑ Fasting/postprandial hypertriglyceridemia ❑ Polycystic ovarian syndrome ❑ Dyslipidemic triad ❑ ↑ lipoprotein ❑ ↑ clotting factors ❑ Inflamamtory markers (e.g. hsCRP or Lipoprotein-associated phospholipase A2 (Lp-PLA2) ❑ Hyperhomocysteinemia ❑ ApoE4 isoform | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Evaluate possible causes of secondary dyslipidemia if suggested by findings during history-taking and physical examination To view a complete list of dyslipidemia causes, click here | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Examine the patient Vital signs | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Order tests to rule out secondary causes of dyslipidemia Common causes include: ❑ Hypothyroidism
❑ Nephrosis
❑ Dysgammaglobulinemia
❑ Cholestatic hepatic diseases
❑ Chronic kidney disease
❑ Type 2 diabetes mellitus
❑ Excessive alcohol intake
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Order fasting lipid profile | |||||||||||||||||||||||||||||||||||||||||||||||||||||||||
Total cholesterol ❑ Optimal: < 200 mg/dL ❑ Borderline: 200-239 mg/dL ❑ High/very high risk: ≥ 240 mg/dL | LDL-C May be either calculated or measured. Measured LDL-C is preferable, especially among certain high-risk populations (elevated triglycerides > 250 mg/dL, diabetes mellitus, peripheral vascular disease). To calculate LDL-C, use the following equation: LDL-C=(total cholesterol-HDL-C)/(triglycerides/5). Do NOT calculate LDL-C when triglycerides > 200 mg/dL (low to no validity of the equation). Instead, use measured LDL-C. ❑ Optimal: < 100 mg/dL ❑ Borderline: 130-160 mg/dL ❑ High risk: 160-189 mg/dL ❑ Very high risk: ≥ 190 mg/dL | HDL-C An optimal HDL-C concentration is a negative CAD risk factor in both genders (subtract 1 risk factor for CAD) ❑ Optimal: ≥ 60 mg/dL ❑ Borderline: 40-50 mg/dL (men) OR 50-59 mg/dL (women) ❑ High/very high risk: < 40 mg/dL (men) OR < 50 mg/dL (women) | Triglycerides ❑ Optimal: < 150 mg/dL ❑ Borderline: 150-199 mg/dL ❑ High risk: 200-499 mg/dL ❑ Very high risk: ≥ 500 mg/dL | Additional tests ❑ Non-HDL non-HDL is calculated by the following equation: non-HDL=total cholesterol - HDL-C non-HDL-C provides additional risk assessment information compared with LDL-C alone. Calculate non-HDL-C only in the following cases: Either moderate elevation of triglyceride (between 200 to 500 mg/dL), diabetes mellitus, insulin resistance syndrome, or established CAD ❑ ApoB ApoB reflects LDL-C particle number, which may be a more potent measure of CVD risk than either LDL-C or LDL-C particle size Optimal: < 90 mg/dL for patients with at risk of CAD (including diabetes mellitus) OR < 80 mg/dL for patients with established CAD or diabetes mellitus plus at least 1 additional risk factor ❑ Ratio of ApoB/ApoAI May be useful in evaluating residual risk (independent of LDL-C) in patients at high risk of CAD or patients with either established CAD, diabetes mellitus, or insulin resistance ❑ hsCRP Order hsCRP for patients with borderline risk or patients with LDL-C < 130 mg/dL hsCRP helps further stratify patient risk for CVD ❑ LP-PLA2 May provide more specificity than hsCRP and may be ordered for further stratification of CVD risk | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Treatment
Confirmed Dyslipidemia | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Set lipid goals ❑ Total cholesterol target: < 200 mg/dL ❑ LDL-C target: < 70 mg/dL for very high risk patients OR < 100 mg/dL for all other patients ❑ HDL-C target: As high as possible. At least > 40 mg/dL in both genders ❑ Non-HDL-C target: 30 mg/dL above LDL-C goal (target < 100 mg/dL for very high risk patients OR < 130 mg/dL for all other patients) ❑ Triglycerides target: < 150 mg/dL | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Control modifiable CAD risk factors ❑ Hypertension ❑ Diabetes mellitus ❑ Obesity | Recommend lifestyle modification ❑ Recommend physical activity
❑ Recommend medical nutrition therapy (reduced calorie intake)
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Lipid goal achieved with lifestyle modification alone? | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Yes | No | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Administer pharmacologic monotherapy Table of available classes, generic names, recommended daily doses, and dose ranges also available below algorithm. Click here. Statins ❑ Lovastatin: Recommended starting daily dose 20 mg PO once daily at bedtime. Dose range: 10-80 mg ❑ Pravastatin: Recommended starting daily dose 40 mg PO once daily at bedtime. Dose range: 10-80 mg ❑ Simvastatin: Recommended starting daily dose 20-40 mg PO once daily at bedtime. Dose range: 5-80 mg (80 mg not approved for therapy unless patient has been on treatment for more than 1 year without myopathy) ❑ Fluvastatin: Recommended starting daily dose 40 mg PO once daily at bedtime. Dose range: 20-80 mg ❑ Atorvastatin: Recommended starting daily dose 10-20 mg PO once daily at bedtime. Dose range: 10-80 mg ❑ Rosuvastatin: Recommended starting daily dose 10 mg PO once daily at bedtime. Dose range: 5-40 mg ❑ Pitavastatin: Recommended starting daily dose 2 mg PO once daily at bedtime. Dose range: 2-4 mg Safety Monitoring with Statins
Fibrates ❑ Gemfibrozil: Recommended starting daily dose 1200 mg PO once daily. Dose range: 1200 mg ❑ Fenofibric acid: Recommended starting daily dose 45-135 mg PO once daily. Dose range: 45-135 mg
Nacin ❑ Immediate release: Recommended starting daily dose 250 mg PO once daily at bedtime. Dose range: 250-3000 mg
Bile acid sequestrants | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Aim to reduce LDL ❑ Statin monotherapy at recommended initial daily dose (LDL reduction: 21% to 55%) ❑ Fibrate monotherapy at recommended initial daily dose (LDL reduction: 20% to 25%) ❑ Niacin monotherapy at recommended initial daily dose (LDL reduction: 10% to 25%) ❑ Bile acid sequestrant monotherapy at recommended initial daily dose (LDL reduction: 10% to 25%) | Aim to reduce triglycerides ❑ Fibrates monotherapy at recommended initial daily dose with or without omega-3 fish oil (triglyceride reduction: 20% to 35%) | Aim to increase HDL ❑ Niacin monotherapy at recommended initial daily dose (HDL increase: 10% to 35%) ❑ Fibrates monotherapy at recommended initial daily dose (HDL increase: 6% to 18%) | |||||||||||||||||||||||||||||||||||||||||||||||||||||
Lipid goal achieved with optimal administration of antilipidemic monotherapy? | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Yes | No | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Does the patient have ANY of the following criteria to initiate combination pharmacotherapy? ❑ Markedly elevated cholesterol concentration, OR ❑ Mixed dyslipidemia (e.g. Hypertriglyceridemia and reduced HDL-C), OR | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
No | Yes | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
❑ Consider changing drug class
| ❑ Consider increasing dose of antilipidemic agent within dose range for each drug
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Lipid goal achieved with optimal administration of antilipidemic monotherapy? | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Yes | No | ||||||||||||||||||||||||||||||||||||||||||||||||||||||
Administer combination therapy Administer ANY of the following combination therapies:
❑ Ezetimibe/simvastatin (1 pill): Recommended starting daily dose 10/20 mg PO once daily at bedtime. Dose range: 10/10 to 10/80 mg, OR | |||||||||||||||||||||||||||||||||||||||||||||||||||||||
Follow-up ❑ Reassess lipid profile at 6 weeks following initiation of management ❑ If goal is not achieved following 6 weeks, reassess 6 weeks later. Continue 6-week interval until target lipid profile is achieved ❑ Once target lipid profile is achieved, generally reassess lipid profile within 6 months to 12 months
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Do's
- Treat pediatric patients who are older than 8 years of age with either LDL-C > 190 mg/dL or LDL > 160 mg/dL plus any of the following conditions: either ≥ 2 CV risk factors even after lifestyle intervention, family history of premature CAD, or overweight/obese/insulin resistance.
Don'ts
- Do not routinely order homocysteine, uric acid, plasminogen activator inhibitor 1, or other inflammatory markers.
- Do not routinely perform non-invasive measures of atherosclerosis (e.g. carotid intima media thickness).
- Do not treat dyslipidemia among post-menopausal women with hormonal replacement therapy.