The landmark Scandinavian Simvastatin Survival Study (4S) published in 1994, may well be remembered as the study that finally put to rest many of the apprehensions and misconceptions regarding lipid-lowering therapy.
DUFFY AND MEREDITH 19961
Dyslipidaemia is the presence of an abnormal lipid/lipoprotein profile in the serum and can be classified as:
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).
Table 87.1Number needed to treat (NNT) with a statin for 1 year to prevent 1 death2 |Favorite Table|Download (.pdf) Table 87.1 Number needed to treat (NNT) with a statin for 1 year to prevent 1 death2
|Risk level ||NNT |
|<5% five-year CV risk ||835 |
|5–10% five-year CV risk ||335 |
|Previous cardiovascular event—high risk3 ||165 |
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.
Table 87.2Common causes of secondary dyslipidaemia |Favorite Table|Download (.pdf) Table 87.2 Common causes of secondary dyslipidaemia
Type 2 diabetes
Obstructive liver disease
Major risk factors for CAD include:
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)
The following fasting tests are recommended in patients every 5 years, starting at age 45 years:
Confirm an initial high result with a second test at 6–8 ...