Epidemiology of Cardiovascular Diseases Flashcards

1
Q

CHD Pathology: Atherosclerosis

A

Atheroma plaque made, mainly of lipids starts to occlude the lumen of an artery
Atheroma plaque ruptures and triggers clotting
Results in a thrombus: CHD IS CAUSED BY ATHEROMA AND THROMBOSIS

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2
Q

What causes an acute MI?

A

If not reopened, the portion of myocardium supplied by that artery will die, causing an infarction.
Depending on the size and other phenomena, the patient may die suddenly or suffer a heart attack, we call it an acute myocardial infarction.

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3
Q

CHD: Typical pattern of disease progression

A

Childhood= coronary atheroma develops silently from childhood
Middle age= manifests as adult disease or death

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4
Q

CHD: Clinical presentations

A

Sudden cardiac death

Heart attack/myocardial infarction

Angina- chest pain on exertion or stress (~70% occlusion)

Progressive heart failure- shortness of breath, ankle oedema, fatigue

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5
Q

CHD epidemiology

A

CHD descriptive epidemiology:
Time, Place, Person

Time: risk increases with age

Place: CHD most prevalent in eastern European countries, low in Mediterranean countries and Japan

Person: more prevalent in men & lower economic backgrounds
- oestrogen seems to protect against CHD but effects stop after menopause

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6
Q

What is a risk factor?

A

any characteristic which identifies a group at increased/decreased risk of disease

  • doesn’t need to be independent, causal, modifiable
  • e.g. age
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7
Q

What is a cause?

A

factor which itself increases risk of disease (prevalence, incidence, mortality)
Cause = biological, not sociocultural phenomenon

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8
Q

Low Quality of Life in CHD patients

A

We measure quality of life with a validated questionnaire like SF36, we can see that for all domains on which we can measure quality of life , coronary heart failure substantially decrease the scores. It measures:
Social function
Physical role limitation
Emotional role limitation
Physical function
Mental health
General health
Energy and vitality
Bodily pain

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9
Q

Survival following Acute MI

A

By 10 years only <25% will survive
Immediately only 50% survive
Half of the deaths will occur without have any chance of reaching hospital, and life saving treatment.

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10
Q

Survival following first admission with CHD

A

Survival is greatly affected by developing any form of chd. But here is shown that substantial differences in prognosis exist.

By far, heart failure has a huge impact on survival probability, greater than that observed with myocardial infarction.

Prognosis is poor in both

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11
Q

Five Year survival after hospital admission- Heart failure worse than common cancers

A

Heart failure is a common occurrence after developing clinical coronary heart disease
And we can see here that 5 year survival of patients in heart failure is actually worse than many very lethal cancers.
It is only beat by lung cancer, as the big killer.

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12
Q

Cardiovascular Diseases

A

Cardiovascular diseases count for about 26% of all UK deaths
The largest single cause is CHD, followed by stroke

Estimated 7+ million people in the UK living with CVD
Estimated 42,245 die under the age of 75 every year

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13
Q

CHD is a big problem for the UK

A

70,000 deaths UK annually, 23,000 premature (<75 years)
CHD accounts for 16% of all male and 10% female deaths
2.3 million living with CHD
relatively high mortality rates internationally
2.5 million years of life lost annually
£6.8 billion costs NHS costs

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14
Q

CHD is a big problem for the NHS (REFERENCE)

A

200,000 Myocardial Infarctions (MIs) per year
30,000 out of hospital cardiac arrests (survival <1 in 10)
Almost 1 million have survived a heart attack
CHD PREVALENCE ~ affects 2.3 million people in UK
(about 1/3 middle-aged & elderly people)
NHS ACTIVITY ANNUALLY (approximate figures)
GPs see 1million individuals
Hospitals admit half a million CHD patients
3.5% NHS admissions UK men, 1.5% UK women
97,000 get angioplasty, & 16,000 CABG (bypass graft)

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15
Q

Describe the iceberg effect

A

People mostly see the visible part of the problem, like MI admissions, incredible attractive stories of life saved by the latest and costlier gadget, or the misery of people mistreated by the overstretched health system.
But a really bigger monster lurk in the darkness, the huge amount of disease not known to the health system, and those healthy people but with risk factors, slowly building up their plaques, waiting for clinical chd to appear.
A huge amount of disease is hidden, but contributing to maintain CHD as the first killer in our society.

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16
Q

Five year CHD death rates in British men aged 35-64 (BRHS)

A

British regional heart study found three main risk factors of CHD in men:
Found that most of the variation in CHD mortality can be explained by:
Smoking status
BP
High or low cholesterol

17
Q

Main factor for acute MI is

A

DIET

18
Q

Prevention

A

PRIMARY PREVENTION = (before disease presents)
SECONDARY PREVENTION = (reduce complications) – if already have symptoms
TERTIARY PREVENTION = (rehabilitation)

19
Q

CHD characteristics

A

CHD has a long asymptomatic phase and the a shorter clinical phase
When we start with symptoms, we know that death is ahead.
This tends to occur at middle age when the symptom threshold has been crossed
But remember that many will experience just death as their first symptom.

What we can do with secondary prevention is improve things, and we can postpone death and control symptoms. But again, peoples dying suddenly will not benefit at all.

20
Q

Primary Prevention

A

Prevention in people who are free from CHD.

2 Methods:
Identify high risk subjects
Reduce risk in entire population

High Risk approach:

21
Q

High Risk Approach

A

We can estimate the risk of developing chd at the individual level with good enough accuracy to recommend its use. By assesing the presence or absence of several patients characteristics, we can estimate the probability of a major event within a certain period.
Categorise patient by key risk factors e.g. sex, age, diabetes status, smoker, BP and cholesterol
QRISK2 score is used to identify subjects with 10 year CVD risk of 10% or more, it uses:
-age and sex
-ethnicity
-deprivation
-systolic BP
-BMI
-BP treatment
-ratio total : HDL cholesterol
-cigarette smoking
-CKD / RA / AF
-diabetes

22
Q

Population Approach

A

rather than focusing on specific high risk individuals:
Try to create a healthier environment for: Deprived, unemplyed, smokers, poor housing, diet.
You try to reduce risk factors in the entire population.
Eg you try and reduce the blood cholesterol level for the entire population.

23
Q

Blood Pressure and CHD risk

A

Risk of CHD is highest for those with high systolic BP

But very few people in the population have BP that high:

Most people have much lower BP
But if we plot the distribution of blood pressure values we see that most of the population lies in the are of lower risk, and the number of deaths is higher as well at lower blood pressure values.
So more CHD occurs in people with only slightly elevated BP, this is because this is where most of the population are.
This shows the importance of a population level approach as a high risk level approach wont help the majority of people

24
Q

NICE Guidance

A

Prevention of cardiovascular disease at population level
Main messages are:
Evidence base for population prevention is surprisingly strong:
meta-analyses & natural experiments
Potentially big disease reductions in diease resulting in
COST SAVING, RAPID, EQUITABLE, ACCEPTABLE

This is done by altering any upstream determinant that affects the downstream causes of disease eg:
Food ⇒ Salt ⇒ Blood Pressure
Food ⇒ Sat Fats ⇒ Cholesterol
Food ⇒ Trans Fats ⇒ Cholesterol

Soft drinks sugar tax
Positive results in Mexico

25
Q

Challenges

A

We know the major factors which cause CHD in practice
Need to understand reasons for social and ethnic differences
Implementing prevention in clinical practice
Implementing population-based strategies for reducing CHD risk
Controlling epidemic in developing world