Cholesterol for idiots!

What is cholesterol?

a lipid (type of fat) plays essential physiological role in the body

Where does it come from?

very little in food, eggs offal shellfish high
saturated fat turned into cholesterol in liver

Why do we need cholesterol?

without cholesterol the body won't work
like specialised bricks it is needed for forming all cell membranes
insulates nerve fibres, allowing chemical messages to travel
synthesis hormones

Why is it bad?

coronary artery disease
disease of arteries

Need to know something about Lipoproteins - the molecules transport cholesterol

Cholesterol on it's own not good enough

Low density lipoproteins (LDL-C) is BAD cholesterol
High density lipoproteins (HDL-C) is GOOD cholesterol
Triglycerides

Plaque formation

Atherosclerosis starts with "fatty streaks" due to oxidised (LDL-C) BAD clinging to walls releasing extracellular cholesterol

Data

Average Total Cholesterol level in UK --> 5.8 mmol/l
Average Total Cholesterol Northumberland --> 6.5 mmol/l
Healthy cholesterol range Total cholesterol less than 5.2 mmol/l
LDL cholesterol less than 3.0 mmol/l
HDL cholesterol more than 1.15mmol/l

British Hyperlipidaemia Society classifies level (Total Cholesterol)

desirable (<5.2 mmol/I)
borderline (5.2 -6.4 mmol/1)
abnormal (6.5-7.8mmol/1)
high (>7.8mmol/1)

Abnormal value - What should we do?

order lipid profile
total cholesterol (TOTAL-C), HDL-C level, Cholesterol / HDL-C ratio

Confused?

So am I

Primary prevention of CHD

Government decided only those with risk of CHD events greater than 30% over 10 years warrant treatment

So what should we be doing?

Secondary Prevention EASY --> all know what to do?

total cholesterol below 5 mmol/l

Primary Prevention NOT so EASY - High cholesterol levels alone poor predictor CHD

identify risk assessment
total cholesterol > 5mmol/l
Sheffield Tables
Framingham Risk calculator

Generally Abnormal Values are:

LDL cholesterol > 4 mmol/litre
HDL cholesterol <1 mmol/litre
Total cholesterol:HDL cholesterol >6.5 mmol/litre

National Service Framework (NSF) for Coronary Heart Disease (CHD)

primary care to achieve goals coronary heart disease prevention
including lipid modification

Cost of achieving CHD NSF lipid-lowering goals £31,000 to £52,000 per GP

Currently

majority English adults have adverse lipid levels
few people on lipid-lowering drugs as currently recommended

Secondary Prevention of CHD

This group most to gain from therapy

smoking
weight exercise
blood pressure below 140/85
low dose aspirin 75 mgs
statins cholesterol less than 5mmol/l
ACE inhibitors
Beta blockers
Warfarin / aspirin for atrial fibrillation
diabetes glucose blood pressure

Currently

only 2.5% adult population taking lipid lowering drugs (statins)
rates low among high risk patients for primary prevention
fewer than 4% individuals eligible for primary prevention receive statins
less than 30% of established CHD are taking statins
total target cholesterol levels are less than 50% in those on treatment

Key message

implementing NSF standards then 8.4% population should be taking statins (age 35-64)
number rise to 14% taking statins (age to 75)

2001

Where are we now?

Doing rather well

77% of our patients with CHD have had a cholesterol measurement

WE MUST IDENTIFY THE REMAINING 13% without a cholesterol measurement

52% with a cholesterol measurement were below 5 mmol/1 --> GOOD
48% with a cholesterol measurement were above 5 mmol/I --> BAD

WE MUST IDENTIFY THIS GROUP AND LOWER THIS LEVEL ACCORDING TO NSF

FACTS AND FIGURES - GROAN

639 of our patients have CHD

Therefore 142 of our NSF criteria patients still no cholesterol measurement

total practice population 10665
number taking statins 383
that is 3.6% of our practice takes statins

Benefits of Statins

How do they work

Biosynthesis precursors --- HMG-CoA reductase enzyme --> cholesterol

Statins act here

demonstrated in 5 randomised placebo-controlled trials (30,000) 4S, WOSCOP, CARE etc.
results suggest risk reduction 34% coronary events in primary prevention

30% coronary events in secondary prevention

statin therapy taken for 5 years seems to reduce stroke by 25% too

So, which drug?

current evidence suggests simvastatin first line prevention

Choice of statin to be used open for debate

Evidence-based medicine suggests simvastatin or pravastatin first choice per major clinical trials

Atorvastatin may be first choice for mixed hyperlipidaemia since reduced triglycerides

Examples

Mrs Shirley S Age 67 years

Clinical data: Hypertension Probable angina Atenolol Fasting

Cholesterol 7.2mmol/l 3.2 - 6.5
Triglyceride 3.66mmol/l 0.79 - 1.97
HDL-CHOL. 1.0 mmol/l 1.2 - 1.7
CHOL/HDL RATIO 7.2

Mrs Felicity H Age 52 years

Clinical Data: Hypercholesterolaemia Brother died MI Heart Failure

Cholesterol 8.2mmol/l 3.2 - 6.5
Triglyceride 0.88 mmol/l 0.79 - 1.97
HDL-CHOL 1.6 mmol/l 1.2 - 1.7
CHOL/HDL RATIO 5.1
LDH-CHOL 6.2 mmol/l 0.0 - 4.2

Mr John M Age 62 years

Clinical Data: C.A.B.G.

Cholesterol 7.4mmol/l 3.2 - 6.5
Triglyceride 1.41 mmol/l 0.79 - 1.97
HDL-CHOL 1.3 mmol/l 1.2 - 1.7
CHOL/HDL RATIO 5.7 mmol/l

A cholesterol protocol

Secondary prevention --> Total cholesterol below 5 mmol/l (proven CHD) (ignore other lipoproteins)

Primary Prevention (risk >30%)--> Total cholesterol to 5 mmol/l or reduce by 30% (which greater)

USE STATINS OR
LDH cholesterol to <3 mmol/l or reduce by 30% (which greater)
OR Total cholesterol:HDL ratio (use Sheffield table)