DYSLIPIDEMIAAhmed M. RashadPGY-1 Family Medicine

Objective

• Definition• Prevalence • Causes

Definition

Dyslipidemias are disorders of lipoprotein metabolism that result in the following abnormalities:

• High total cholesterol (TC) • High low-density lipoprotein cholesterol (LDL-C) • Low high-density lipoprotein cholesterol (HDL-C) • High triglycerides (TG)

Prevalence

• More than 100 million Americans, about one third of the population have total cholesterol levels more than 200 mg/dL.

• Total cost associated with CVD and stroke in the US many of which are related to dyslipidemia is estimated to be more than $400 billion in 2006

• It is estimated that hyperlipidemia prevalence is around 25% in the state of Qatar

• American Heart Association. Cholesterol Statistics. Available at: www.americanheart.org/presenter.jhtml? identifier=536. Accessed November 20, 2006

• High Cholesterol: Do you really understand it?. [Online]. 2010 Oct 5 [cited 2011 Sep 26]; Available from: URL: http://www.thepeninsulaqatar.com/health/128194-high-cholesteroldo-you-really-understand-it.html

Prevalence

The prevalence of dyslipidemia varies with the population being studied. The prevalence is highest in patients with premature coronary heart disease (CHD), which can be defined as occurring before 55 to 60 years of age in men and before 65 years in women. In this setting, the prevalence of dyslipidemia is as high as 75 to 85 percent compared to approximately 40 to 48 percent in age-matched controls without CHD

PrimaryGenetic Disorders

SecondaryDiabetes

Nephrotic Syndrome

Hypothyroidism

Drug – Induced

Hypertension

Causes

Familial Hypercholesterolemia• Familial hypercholesterolemia (FH) is a genetically

modulated clinical syndrome in which the phenotype is characterized by a high LDL-C level from birth, a propensity to tendon xanthomata, and early onset CHD.

• Its established causes are LDLR mutations (most common), gain-of-function PCSK9 mutations (<5 percent of cases in most clinics), and familial defective apoB (<5 percent of cases), generally the apoB3500 mutation.

PRIMARY DYSLIPIDEMIA (Fredrickson’s Classification)

Type Primary Lipid Elevation

Lipoprotein Occurrence

I TG Chylomicrons Rare

IIa C LDL Common

IIb C, TG LDL, VLDL Most Common

III C, TG IDL Rare

IV TG VLDL Common

V TG VLDL, Chylomicrons

Rare

Practical Therapeutics, AFP, 1998

Secondary Causes of Dyslipidemia

• Hypothyroidism• Nephrotic syndrome• Obstructive liver disease• Diabetes mellitus• Chronic renal insufficiency• Cushing disease• Drugs (oral contraceptives, diuretics)

References

• American Heart Association. Heart Disease and Stroke Statistics—2004 Update. Dallas, Tex: American Heart Association; 2003.

• Grundy SM, Cleeman JI, Merz CN, Brewer HB Jr, Clark LT, Hunninghake DB, Pasternak RC, Smith SC Jr, Stone NJ. Implications of recent clinical trials for the National Cholesterol Education Program Adult Treatment Panel III guidelines. J Am Coll Cardiol. 2004; 44: 720–732. Abstract/FREE Full Text

• Fredrickson, DS; Lees, RS (1965). "A system for phenotyping hyperlipoproteinemia" (PDF). Circulation 31 (3): 321–7. doi:10.1161/01.CIR.31.3.321. PMID 14262568.

• James, William D.; Berger, Timothy G.; et al. (2006). Andrews' Diseases of the Skin: clinical Dermatology. Saunders Elsevier. ISBN 0-7216-2921-0.