What is the definition of dyslipidemia?

Definition of Dyslipidemia

Dyslipidemia is defined as abnormal levels of lipids in the blood, characterized by elevations in total cholesterol (TC), low-density lipoprotein cholesterol (LDL-C), non-high-density lipoprotein cholesterol (non-HDL-C), triglycerides, or some combination thereof, as well as lower levels of high-density lipoprotein cholesterol (HDL-C). 1

Types of Dyslipidemia

Dyslipidemia can be categorized into two main types:

1. Primary (Genetic/Familial) Dyslipidemia

• Familial Hypercholesterolemia:

  • Characterized by highly elevated LDL-C levels (≥190 mg/dL)
  • Genetic mutation affecting LDL receptor function
  • Occurs in approximately 1 in 200-500 persons in North America and Europe 1
  • Higher prevalence in populations with known founder effects (up to 1 in 100 persons)

• Familial Hypoalphalipoproteinemia:

  • Characterized by isolated low HDL cholesterol levels
  • Associated with autosomal-dominant inheritance
  • Linked to decreased HDL production or mutations in apolipoprotein A1 1

• Dysbetalipoproteinemia (Type III Hyperlipoproteinemia):

  • Characterized by elevations of both cholesterol and triglycerides
  • Associated with autosomal-recessive inheritance
  • May present with palmar xanthomas and tuberous/eruptive xanthomata 1

2. Secondary (Multifactorial) Dyslipidemia

• Caused by polygenic and environmental factors, including:

  • Obesity
  • Diabetes mellitus
  • Unhealthy lifestyle
  • Certain medications (corticosteroids, isotretinoin, cyclosporin)
  • Medical conditions (Cushing's syndrome, liver/kidney diseases)
  • Alcohol abuse 1, 2

• Multifactorial Dyslipidemia Definition:

  • Elevations in LDL-C (≥130 mg/dL)
  • TC (≥200 mg/dL)
  • Or both, not attributable to familial hypercholesterolemia 1

Specific Lipid Abnormalities

Atherogenic Dyslipidemia

• Characterized by:
  • High triglyceride levels
  • Low HDL-C levels
  • Presence of small, dense LDL particles
  • Highly prevalent in patients with diabetes or metabolic syndrome
  • Increases cardiovascular disease risk 2

Hypertriglyceridemia

• Defined as elevated triglyceride levels
• Classification:
  • Moderate: 150-499 mg/dL (requires lifestyle modification)
  • Severe: ≥500 mg/dL (requires pharmacological intervention)
  • Very severe: >1000 mg/dL (requires urgent treatment to prevent pancreatitis) 3

Clinical Significance

Dyslipidemia is a major risk factor for cardiovascular disease:

• Elevated LDL-C is the 8th leading risk factor for death globally as of 2019 2
• Associated with increased risk of atherosclerosis and cardiovascular events
• In specific populations (e.g., transplant recipients, patients with peripheral artery disease), dyslipidemia management is a priority regardless of baseline lipid levels 1

Measurement and Monitoring

• Standard Lipid Panel includes:

  • Total cholesterol
  • LDL cholesterol
  • HDL cholesterol
  • Triglycerides

• Non-HDL Cholesterol:

  • Comprises cholesterol in LDL, intermediate-density lipoprotein, and VLDL particles
  • Calculated by subtracting HDL cholesterol from total cholesterol
  • Better predictor of CVD risk than LDL cholesterol in some cases
  • Particularly useful when triglyceride levels are elevated (>400 mg/dL) 1

• Apolipoprotein Measurements:

  • ApoB/ApoA ratio - associated with cardiovascular risk
  • Elevated in patients with obesity and metabolic disorders 1

Understanding the definition and classification of dyslipidemia is essential for appropriate risk stratification and treatment planning to reduce cardiovascular morbidity and mortality.