Dyslipidemia

Dyslipidemia is a major risk factor for atherosclerosis. Most evidence specifically implicates cholesterol - in particular low density lipoprotein (LDL), the delivery mechanism of cholesterol to the tissues. Elevated cholesterol levels are sufficient to induce plaque development, even if other risk factors are absent. High density lipoprotein (HDL), in contrast, is believed to mobilize cholesterol from developing and existing atheromas and transport it to the liver for excretion in the bile.

 

 

 

Assessment of Dyslipidemia

Lipid profiles include fasting total cholesterol, LDL, HDL, and triglycerides. Lipid levels should be measured every 5 years in healthy adults. More frequent screening/follow-up should be done in people with established risk factors.

 

Signs of hyperlipidemia can be seen on physical exam, and include:

 

Management of Dyslipidemia

  • target levels
  • lifestyle modification
  • medications
  • isolated hypertriglyceridema

Target Levels

 

Target lipid values, and treatment plans, depend upon risk category (McPherson et al, 2006).

risk category

LDL (mmol/L)

ratio total/HDL

high (10 yr risk >20%, or Hx of DM or CAD)

<2.0 (<100)

<4

medium (10 yr risk 11-19%)

<3.5 (<130)

<5

low (10 yr risk <10%)

<5.0 (<130 with 2 or more risk factors, <160 with 0-1 risk factors)

<6

 

 

If dyslipidemia is found, screen for secondary causes, including hypothyroidism, chronic kidney disease, diabetes mellitus, nephrotic syndrome, and liver disease.

Lifestyle Modification

Lifestyle approaches should be taken for at least 3 months before considering drug therapy.

High dietary intake of cholesterol and animal fats raises plasma cholesterol levels, while a low ratio of staurated-to-unsaturated fats lowers them.

  • less than 7% of calories should be from saturated fat
  • omega-3 fatty acids seem particularly beneficial.
  • increase dietary fibre

Stop smoking.

Medications

Statins are the first line treatment. They decrease cholesterol production and increase LDL uptake. Myopathy and hepatotoxicity are rare but must be considered.

After initiating drug therapy, lipids should be measured at 6 weeks and 3 months.

Monitor ALT, AST, CK at baseline and every 6 weeks.

 

Other medications include:

  • fibrates - increase HDL and decrease TAG levels
  • niacin - a vitamin which lowers VLDL synthesis in the liver
  • ezetimibe - inhibits cholesterol absorption in the gut
  • bile acid resins

Isolated Hypertriglyceridemia

An elevated TG but normal LDL and ratio should be principally managed with lifestyle modifications: weight loss, exercise, avoidance of smoking and alcohol, blood glucose control, and increase omega-3 fatty acid intake.

 

 

Resources and References

 

McPherson R et al. 2006. Canadian Cardiovascular Society position statement--recommendations for the diagnosis and treatment of dyslipidemia and prevention of cardiovascular disease. Canadian Journal of Cardiology. 22(11):913-27.