Lecture 10. Public Health 1: Definitions and Measures

Question 1

What is demography?

Answer 1

The study of populations

Question 2

What is population size dependent on?

Answer 2

Birth, death, immigration and emigration

Question 3

How is the information required to enumerate the population collected?

Answer 3

Through registrations and census

Question 4

What is epidemiology?

Answer 4

The branch of medical science concerned with the incidence and distribution of disease

Question 5

What is epidemiology a branch of?

Answer 5

Ecology

Question 6

What is public health?

Answer 6

Improving the health of the population (can be whole population or subdivided into subpopulations)

Question 7

What does improving the health of the population mean?

Answer 7

Rather than treating the diseases of individual patients (that’s medicine not public health)
We must know the “health of the population”
Interventions to improve the “health of the population”

Question 8

What is the easiest way to measure public health?

Answer 8

Deaths (mortality)
Unambiguous; easily counted
“Healthy people don’t die”
Is final – there is no prevalence of death, only incidence

Question 9

What was one of the first examples of public health related measurements of death by cause?

Answer 9

Florence Nightingale recording deaths in the Crimean War

Question 10

What are ICD-10 codes?

Answer 10

Origins in 1850s and managed by WHO
Codes change over time (C62 = AIDS)
These are y clinical diagnosis, not by “cause”

Question 11

How many people die in the UK each year?

Answer 11

~550,000

Question 12

What are ~80% of deaths in >54 year olds due to?

Answer 12

Circulatory, respiratory and neoplasm

Question 13

What are ~60% of deaths in the 15-24 year old age group olds due to?

Answer 13

External factors
Accidents, self-harm, assaults (codes V01-Y89)

Question 14

What do deaths before age at the “expected” death result in?

Answer 14

Loss of life years

Question 15

How is public health improved?

Answer 15

When the number of life-years is increased

Question 16

What does life-years gained (LYG) mean?

Answer 16

If 1000 people live a year longer than expected then it’s 1000 LYG

Question 17

What does potential years of life-lost (PYLL) mean?

Answer 17

How many life years does a disease take away from a population

Question 18

What do mortality measures assume?

Answer 18

That all life-years are equal (saving one year of life of an 80 year old is the same as a 5 year old)
Doesn’t account for age at which they lived or disability etc

Question 19

What are the current UK life expectancies at birth?

Answer 19

Male: 77 yrs
Female: 82 yrs

Question 20

When can life expectancy be calculated?

Answer 20

At any age

Question 21

What are responsible for great losses of healthy life?

Answer 21

Many diseases such as paralysis and chronic depression
Common and long-lasting demands on healthcare

Question 22

What does QALY mean?

Answer 22

Quality adjusted-life year - usually gain of life-years

Question 23

What does QALY mean?

Answer 23

Relative measure of the future stream of disability-free life lost as a result of death, disease & injury

Question 24

If you expect to live for 23 years and remain in perfect health, how many DALYs are lost?

Answer 24

23 DALYs (same as LYG)

Question 25

If you expect to live for 23 years but become blind where a year of life is valued at 0.6 (ie 60% of a healthy life), how many DALYs are lost?

Answer 25

23*0.4 = 9.2 DALYs

Question 26

What does disability weighting measure?

Answer 26

Prevalence rather than incidence

Question 27

What can disability weights be?

Answer 27

Culturally specific (better to be blind in the devloped world than the less developed)
Negative

Question 28

What is important to consider when discussing disability weighting?

Answer 28

Disability weights are open to some interpretation, and different approaches are continually being developed

Question 29

What does the EQ-5D score measure?

Answer 29

Level of independence of a person (can you get out of bed on your own, can you cook etc)

Question 30

What is one of the biggest problems when it comes to disability weighting?

Answer 30

Children are not accounted for (have extremely low EQ-5D) so most graphs start at around 20

Question 31

What do certain cultures account or which the UK does not?

Answer 31

Age weighting
Some cultures value those who’ve lived longer lives less “fair-innings’
In the UK all ages are valued equally

Question 32

What is time preferencing?

Answer 32

Discounting - the value of a life decreases into the future
Might swap five years of health in the future for one healthy year now

Question 33

What do DALYs enable use to examine?

Answer 33

Enables “burden of disease” to be measured
Enables cost-effectiveness analyses
See the impact on the healthcare industry

Question 34

How many PYLL per year in the UK?

Answer 34

~3 million
~6 years per death (people dying early due to various diseases and such)

Question 35

The rank order of cause is similar to death apart from what?

Answer 35

External causes
Deaths that happen younger have greater impact

Question 36

How many DALys are lost annually in the UK?

Answer 36

~7.8 million

Question 37

Although ischaemic heart disease remains at the top, why are neuropsychiatric disorders ranked above neoplasms?

Answer 37

Neuropsychiatric disorders are a much greater burden than neoplasms
Mental issues will probably top cardiovascular in the future

Question 38

How much money from the government is given to “public health”

Answer 38

Unknown, however public health includes elements of all aspects of government spending

Question 39

Given limited resources, how do we decide between interventions?

Answer 39

Choice between saving 1 life or 5 lives at the same “cost”, choose 5 lives
Otherwise, no basis for choosing when a choice must be made
Requires that we measure the effects of costs

Question 40

What is cost-effectiveness?

Answer 40

Division of health benefit
Interventions (e.g. immunisation, chemotherapy, intensive care wards) buy DALYs
Choose those interventions that buy the most health (LYG per £ or DALY per £)
The only way of rationally deciding between interventions when resources are finite

Question 41

What is NICE?

Answer 41

UK National Institute of Health and Clinical Excellence (created to avoid politically difficult decisions)
Creates clinical guidelines (e.g. which drugs should be prescribed, which treatments should be used)
Uses combination of effectiveness (e.g clinical trials) and cost

Question 42

What does NICE not account for?

Answer 42

No age weighting; discounts both outcomes & costs
No account of “total cost”
An intervention that costs less than £X to save a DALY is considered cost effective

Question 43

How much money is each DALY currently?

Answer 43

~£20,000-30,000 paid by the government to keep a person healthy for a year

Question 44

Why is there tension between the DoH/NHS and the pharmaceutical industry?

Answer 44

UK trying to set price limits on drugs – Pharmaceutical industry trying to break the limits

Question 45

What other roles does NICE have?

Answer 45

Public health – Increasingly used for public health decision-making (read *)
Value-based pricing – NICE now has a central role in determining the value of a drug/intervention and therefore the
price that the NHS will pay
Social care – NICE’s role has expanded to include developing guidance and quality standards for adults and children’s services
Trying to expand into all areas that impact an individual’s health

Question 46

What are examples of public health interventions?

Answer 46

Eduction - empowerment
Mass screening/testing - immunisation; breast cancer; helminths
Diet - Micronutrient supplementation (school milk)
Fertility - contraception; maternal health
Drugs - tobacco, alcohol, illegal
Water/sanitation
Pollution

Question 47

When talking about maximising the health of a population, do we talk about morbidity or death?

Answer 47

Morbidity