Lipids All you ever wanted to know but were afraid to ask…

Shelagh ClearyVascular Programme Manager Dudley Office of Public Health

Do we need cholesterol?

Where do we get it from?

Lipid breakdownVery large and dense lipid molecules are broken down to

release energy for the cells of the body to use.

As this process continues they get smaller and smaller and eventually leave the final circulating particles in the blood stream

These are the particles we look at when we look at lipid results from blood test reports

Lipid profile

Final particlesTotal cholesterol is the value given for HDL, LDL and

triglycerides combined – the “total”If we just look at the total it does not give us enough

information, because….

High Density Lipids or HDL is anti-artherogenic

Low Density Lipids or LDL is pro-artherogenic

Atheroma build up The purpose of analysing lipids is to determine whether

there is likely to be a build up of atheroma in the arteries.

Atheroma build up leads to the development of CVD and to conditions such as heart attack and stroke.

So optimally, we would need: A high level of the anti-artherogenic particles – HDL

and A low level of pro-artherogenic particles - LDL

Why?Unused LDL is oxidised and then forms atheromatous

plaques on the inside walls of the arteries, causing them to become narrowed or even blocked.

HDL absorbs the unused LDL and takes it back to the liver before it can become oxidised.

So either a low level of HDL, or a high level of LDL (or both) causes more atheromatous plaques to be formed - Mismatch

So what should the levels be?

Target levels Cholesterol - less than 5.0 in primary prevention, but less

than 4.0 in secondary prevention

HDL - at least 1.0, but at least 1.2 in females and people with diabetes

Ratio - less than 4.0 – 5.0

LDL - less than 3.0 in primary prevention, but less than 2.0 in secondary prevention.

Triglycerides - less than 1.7

CVD Risk AssessmentJust looking at total cholesterol does not tell us enoughWe need to understand how much of this total is made

up of the good lipids and how much of the badFor primary prevention risk assessment we use the ratio

of total cholesterol to HDL:

Ratio = Total cholesterol HDL

Importance of ratioThis gives a better indication than TC alone of the overall

impact of the lipids on the development of atherosclerosis.

E.g. work out the ratios….55 year old male TC 5.6, HDL 0.8 = 7.055 year old female TC 5.6, HDL 1.2 = 4.655 year old female TC 7.0, HDL 1.5 = 4.6

If the target levels are raisedThe iCAP software will identify anyone with a total

cholesterol or a ratio of 5 or more in the workflow.

Then:Explain the resultsGive advice on reducing cholesterol in the dietA repeat test is indicated in 3 months timeIf the cholesterol is still raised at 3 months and the CVD

risk is 20% or more, then the GP may commence lipid lowering medication.

But remember ratio…..Remember the ratio is a better guide to the impact of the

lipids and the development of atheroma, so:If the total cholesterol is raised but the ratio is normal,

then just give advice on a low cholesterol dietIf the cholesterol is normal but the ratio is raised, give

advice and follow with a repeat blood test in 3 months to re-check

Familial HyperlipidaemiaHereditary condition - heterozygous (approximately 1 in 500 of the U.K.)

High levels of lipids are present from birth. The disease is genetic, autosomal dominant. Children of a person with FH have a 50 per cent risk of having FH.

The disease does not skip generations which means that children and grandchildren of family members who do not have a defective gene are therefore not at risk from FH

In all the cells of the body there is a receptor that allows LDL to be cleared from the bloodstream.

People with FH have a defect in the gene responsible for this LDL receptor. This causes an accumulation of LDL in the blood and ultimately in the arterial vessel walls.

Well researched area, more than 300 known gene defects that lead to FH.

Diagnosis of FH – Simon Broome CriteriaTC >7.5mmol/l LDL>4.9mmol/l, plus

Tendon xanthoma in the person or 1st/ 2nd degree relative

Other signs Corneal arcus Development of premature CVD History of premature familial CVD

Premature CVD: Male developing CVD at or below 55 years, Female developing CVD at or below 65 years. Premature Familial CVD:Father/brother-developing CVD at or below 55 yearsMother/sister developing CVD at or below 65 years

N.B. CVD risk calculators or tables cannot be used to asses patients with familial hyperlipidaemia.

F.H. Xanthalasma Corneal Arcus

Tendon Xanthoma

F.H.The iCAP software will identify anyone with possible FH.

ALL patients with suspected F.H. should be referred to the GP urgently for assessment and possible specialist referral / assessment of family members

N.B. The risk calculation software cannot be used to calculate risk scores for people with FH

Explain this to the patient – it will be underestimated if they have FH

What will lower cholesterol?Low cholesterol diet – remember the liver makes it too!Increasing physical activity and exerciseAvoiding stress

What about ..?Smoking Alcohol

Low cholesterol dietSwitch to mono or poly-unsaturated fats (30%)Reduce saturated fat (10%)

Butter, cream, full fat milkMeat, burgers, sausagesProcessed foods, pies, ready mealsCakes, biscuits, chocolate, crispsUse healthier cooking methods

Coffee time?

So,… Is this patient diabetic?

Sweet success with checking blood glucose results

Type 2 diabetesType 2 diabetes is not a single disorder but part of a

much broader metabolic syndrome:

This consists predominantly of insulin resistance.

Insulin resistance results from hereditary and lifestyle factors involving over nutrition and under activity. It is associated with obesity, particularly abdominal obesity.

Nature versus nurture?

Insulin resistance

Insulin resistance causes high levels of glucose and insulin in the blood

High levels of insulin cause problems with the lipid profile, raising triglycerides and LDL and lowering HDL.

It therefore helps to make more atheromatous plaques develop

Impaired glucose regulationThe regulation of glucose can be impaired for several

years before diabetes is diagnosed. This period is called impaired glucose regulation or a pre-diabetic state.

Diabetes may be prevented by management of people with impaired glucose regulation

Pre-diabetic state …. how do we find it?

Diagnosing IGR

Fasting glucose testIf the fasting glucose is 6.0 or below, then this is normalIf the fasting glucose is 6.1 – 6.9, then this may be

impaired fasting glucose or IFG or impaired glucose tolerance IGT

If the fasting glucose is 7.0 or more, then this may be diabetes

Non-Fasting glucoseUsing the point of care finger prick blood testAsk when the patient last ate a meal or snackIf this is more than 2 hours before the glucose should be

6.0 or lessIf it is less than 2 hours the glucose should be no more

than 11.0

Less than 2 hours - 6.0 or lessMore than 2 hours - No more than 11.0

What is in iCAP?iCAP will highlight any glucose result over 6.0 and

recommend a 2nd test to confirm.Explain to the patient that they should see their GP or

practice nurse to arrange a 2nd test if this is requiredTake into account other risk factors for diabetesWhere a diagnosis is to be considered the practice may

send them for / carry out an oral glucose tolerance test (OGTT)

Oral Glucose Tolerance testAn OGTT is requested to confirm either diabetes or

impaired glucose toleranceWhat the test involves:

Fasting specimenGlucose load2 hour post load specimen

This shows any problems with the way that glucose is processed in the body which may give the diagnosis of IGT or diabetes

ReferralSo….,Arrange for a second test for anyone with A fasting glucose of 6.1 or more, orA non-fasting glucose which is: More than 6.0 if they have not eaten in the last 2 hours, orMore than 11.0 if they have eaten in the last 2 hours

Ask them to see the practice nurse or GP with the resultsDudley Diabetes Website www.dudleydiabetes.co.uk

Any questions….?

Kidney functionWhat’s pee got to do, got to do with it…?

Kidney function

Kidney impairment is a major cause of heart attack and stroke and is associated strongly with hypertension

The process by which we measure kidney function is the rate at which the kidneys are able to filter the arterial blood stream

This is called the Glomerular Filtration Rate or GFR.It is calculated from levels of creatinine in the blood and

so is called an estimated GFR or eGFR

Chronic Kidney DiseaseA diagnosis of moderate chronic kidney disease is made

when the eGFR is less than 60 mls/min

An eGFR of 59 or less would possibly indicate a CKD stage of 3, 4 or 5

These stages are moderate to severe kidney disease. At these levels the incidence of cardiovascular disease is 10 fold.

CKD and CVDCKD causes blood pressure to rise which causes a heavy

workload on the heart

CKD causes levels of protein in the urine to become raised leading to oedema, also causing blood pressure to rise and further increasing the workload of the heart.

CKD and CVDCKD causes calcium to be taken from the bones and into

the blood stream where it is deposited in the arteries and heart valves. This causes stiff and narrowed vessels and problems with the pumping mechanism of the heart

CKD causes anaemia, which increases the workload of the heart as it has to pump the blood faster to maintain perfusion. There can also be loss of perfusion to the heart itself.

What is on iCAP?The eGFR result will be displayed.

If the result is lower than 60 then it will stage the level of possible CKD, i.e. Possible CKD Stage 3, 4 or 5

Any result of less than 60 will be included in the workflow along with the next step of the pathway

The next step would be to repeat the eGFR test after a period of 3 months – advise the patient

What about dementia?

The incidence of dementia rises with ageThe incidence in the UK is rising rapidlyThe risk factors for CVD are the same as for dementia –

especially vascular dementiaIf the patient is over 65, then icap will prompt you to

advise the patient of this additional riskGive leaflet supplied by DoH

Any questions….?

Assessing CVD risk scores

So what are the odds…..?

CVD Risk CalculationRisk scores are automatically calculated on the iCAP

software.The risk is displayed as latest risk, relative risk and target

risk.Latest risk is the risk calculated on the entries made. This

is also called absolute risk.Relative risk is what level of risk would be expected for an

individualTarget risk shows what happens to risk when values are

changed, i.e. smoker to non-smoker

Communication of riskRisk of 1-9% is low riskRisk of 10-19% is moderate riskRisk of 20% or more is high riskUse odds, e.g. 1 in 5, 1 in 4 etcHeart age – probably more meaningful and more

powerful to communicate risk to patientsBus queueComparison of absolute risk to relative risk

High riskThose found to be at high risk are added to a high risk

register

They will be called for review annually using the software.

People at this level of risk can be prescribed lipid lowering drugs

More intensive targeting of risk factors

ReferralGive advice to:

Anyone who is high risk, especially where this is unexpected, i.e. where the relative risk is low and there are clinical indications to account for this, e.g. raised blood pressure or lipids.

Anyone who has a higher absolute risk than expected / relative risk level, even if this is moderate or low

Risk factors will have been identified which can account for the increased level of risk

These risk factors need to be reduced where possible to reduce the level of risk – use target risk to demonstrate this

So, what are the risk factors…?

Any questions….?

Risk assessment can be a good thing…….

Wish I’d done a risk

assessment!