Chapter 87: Dyslipidaemia

INTRODUCTION

Dyslipidaemia is the presence of an abnormal lipid/lipoprotein profile in the serum and can be classified as:

• predominant hypertriglyceridaemia

• predominant hypercholesterolaemia

• mixed pattern with elevation of both cholesterol and triglyceride (TG)

Modern epidemiological studies have established the facts that elevated plasma cholesterol causes pathological changes in the arterial wall leading to CAD, and that lipid-lowering therapy results in reduction of coronary and cerebrovascular events with improved survival.

A Cochrane systematic review² of 18 large RCTs found high quality evidence that statins reduce all-cause mortality and major vascular events. The number needed to treat (NNT) with statins varies markedly depending on the risk category the person falls into (see TABLE 87.1).

The main focus of treatment will be on primary dyslipidaemia but secondary causes (see TABLE 87.2) also need to be addressed. LDL-C is the lipid with the highest correlation with CHD and its level remains the primary target of lipid modifying therapy. The statins are the first-line therapy for a raised level. Like total cholesterol measurement, LDL-C should not be used in isolation.

ESTABLISHED FACTS^4,5,6

• Major risk factors for CAD include:

  • – increased LDL cholesterol + reduced HDL cholesterol

  • – ratio LDL-C:HDL-C >4

• Risk increases with increasing cholesterol levels

• TG level >10 mmol/L increases risk of pancreatitis

• Management should be correlated with risk factors

• 10% reduction of total cholesterol gives 20% reduction in CAD after 3 years

• LDL-C reduction with statin therapy reduces heart attacks, stroke, the need for revascularisation and death

• Screening is recommended 5 yearly from age 45 years (Aboriginal and Torres Strait Islander people from 35 years)

INVESTIGATIONS⁵

The following fasting tests are recommended in patients every 5 years, starting at age 45 years:

• serum cholesterol level, HDL-C, LDL-C and triglyceride (TG)

Confirm an initial high result with a second test at 6–8 ...