Valuing health

Question 1

Why do we need to value health?

Answer 1

For example in cost utility analysises, need to value someones health from 1- perfect to 0-as good as dead, to calculate the QALYs. Allows morbidity to be taken into account as well as mortality.

Question 2

How can a vignette be used to value health? (3 negatives)

Answer 2

patients symptoms are described in a paragraph and this could be valued by experts or members of the public
(-) could be bias depending on how written, who ask.
(-) time, cost
(-) lack comparabiltiy to other diseases

Question 3

How can a Visual analogue scale (VAS) be used to value health?

Answer 3

Descibe different health states/ symptoms and public or expert panel value these states on a sliding scale often 0(usually dead)-100. These can then be weighted to give the total utility.

Can ask them their dead number as may perceive some diseases worse than dead.
Calculation: Value-dead value/100-dead.
Usually value/ 100 e.g. 80/100 =0.8 so in right units 0-1.
Some argue this isnt utility and needs conversion into SG utilities.

Question 4

How can Time Trade Off (TTO) be used to value health?

Answer 4

Public given 2 options to choose between- one with the length of life in the health state to be valued, the other a shorter period in full health.
The period in full health gets reduced until the two are valued equally, e.g. 8 years with diohhreah prefered over 3 years in full health, but equalled to 4 years in full health, therefore the utility =0.5 (4/8) and 4 QALYs.

Question 5

How can Person Trade Off (PTO) be used to value health?

Answer 5

Similar to TTO, but have to chose between 2 groups- 1 group with X number of people with a condition or

Question 6

How can standard gamble be used to value health?

Answer 6

Individuals asked to choose between living in a poor health state vs an uncertain option of less than 100% chance of perfect health or 100% chance of dying immediately.
E.g. prefer state A or a 90% chance of restoring full health etc until they balance.
So if State A equals a 60% chance of restoring full health, the utility would be 0.6.

The more severe the health state the Lower the risk of getting to perfect health (Or greater is the risk of death)that the patient would accept to be cured of it

Question 7

How can Discrete Choice Experiments (DCE) be used to value health?

Answer 7

Choose between two health states until they balance- one will have prior utility value attatched.

Question 8

Which health valuation methods involve an opportunity cost decision making aspect?

Answer 8

Person trade off, time trade off, standard gamble, Discrete choice experiements can do, but VAS doesnt- no choice involved between two options just a scale- scaling biases.

Question 9

Which health valuation methods involve the use of an interval scale?

Answer 9

Person trade off, time trade off, standard gamble, Discrete choice experiements can do, but VASunknow. How can we know if utilities values 0-100 for that person have interval properties or not? 90-100, the same diffference as 20-30?

Question 10

Which health valuation methods involve an economic theory basis?

Answer 10

Person trade off, standard gamble, Discrete choice experiements do, but VAS and time trade off doesnt

Question 11

Which health valuation methods incorporate other ‘issues’?

Answer 11

None of them, Person trade off is the only one which hints at this- by considering people as people and considering societal aspects.

Question 12

Which health valuation methods include uncertainity?

Answer 12

Only standard gamble

Question 13

Cheap and easiest health valuation methods to administer?

Answer 13

VAS and Discrete choice experiements

Question 14

For and against the general public being the people to value health?

Answer 14

(+) Tax payers- want their say in economic spending
(+) Have no vested interest in the trial- unbias
(-) lack of strategy or experience of that symptom, could be bias as some people not able to give their views e.g. children, elderly, sick etc.

Question 15

For and against the patients being the people to value health?

Answer 15

(+)Their pain, they understand the hardship and gives patients a voice.
(-) Lack of perspective- could be particularly fed up that day or get used to the lower standard and be in denial, and may not all be able to participate if ill.
(-) They may value their health as worse with the knowledge that this could help them get treatment.

Question 16

For and against experts being the people to value health?

Answer 16

(+) will have a better understanding than the public and more strategic, and can answer when the patient cannot
(-) not as good as a patient

Question 17

Why may a generic preference based measure be used instead of specific disease health valuation methods?

Answer 17

(+) Cheap, off-the shelf to develop and pilot new VAS questions etc, is timely and costly for every CUA, so a standardised method would be much quicker.
(+) a standardised survey is the same across every disease so the results are highly comparable, whereas different VAS scales for different diseases are less so.
(+) standardised method for comparison between trials, as other methods utility values may vary depending on hwo they are done etc/ which method used.
(+) can capture health holistically and take into account the patients preferences and values e.g. leisure activities, self worth etc.
(+) easy for patient to use at RCT
(+) NICE and other agencies include in their reference case

Question 18

WHat is a generic preference based measures (GPBM)?

Answer 18

A generic survey for patients to fill out on a range of health aspects e.g. pain, anxiety/depression, usual activity, mobility, self-care (5 domains).
E.g. on either a 3 level scale of newer 5= EQ-5D .
The UK values are based upon Time-trade off, but other countries may use VAS or SG for HUI3 or VAS for SF-6D for patients to value their health.

Question 19

Disadvantages of Generic preference-based measures?

Answer 19

(-) May not always be relevent or sensitive to specific symptoms or show treatment effects well.
(-) different surveys can get different results- how accurate?

Question 20

condition specific preference-based measures?

Answer 20

Some have been developed for children, or public health which is hard to evidence, or specific conditions like visual impairements.

Question 21

Most common valuation method used to work out QALYs?

Answer 21

Time trade off method mainly used in HICs or MICs.

Question 22

Valuation for DALYs?

Answer 22

220 common health states are described with the aim to be used across the world. This is mainly used in LICs and MICs. Attatching utilty states to these is still challenging however.

Question 23

Are QALYs/ DALYs all equal?

Answer 23

Economic evaluations count them all as equal.
Efficiency argument argues no- greater weight on DALYs when in working age as this is most cost effective, but equity stance questions this, as then reagrds children, elderly and low socioeconomic backgrounds as worth less?

Some QALYs can also impact others or have other societal impacts not captured. E.g. someone needs family care all day.

Question 24

When using patient health valuing may the health be overestimated?

Answer 24

SG and TTO have found in the past that patients are uwilling to gamble anything for their health condition/ give any years away- which would give the result of having a perfect utility when they obviously dont.

Years may be too long- but would sacrifice e.g. 3 months giving utility 9.75, but then at least not seen as perfect.

Question 25

How is eQ-5D utility calculated?

Answer 25

1= no utility loss, whereas 2 and 3 give a utility loss. The sections are not all eqully weighted so different utility losses for different sections, and obviously more for 3 than 2. Therefore the end score is negative.
Start at 1- (constant 0.081 if any loss in utility) - (..X1)- 2(…X2)- (…X5)
Where x1=2, X2=3 and X5=2 and X3 and X4=1

Question 26

Why may Generic Preference-Based measures scores vary for the same patients?

Answer 26

Descriptive System
Dimensions – e.g. visual function not covered by EQ-5D
Severity – range (e.g. floor effect in SF-6D)
Sensitivity – number of levels (e.g. EQ-5D-3L is very crude at upper end)
Valuation
Valuation methods are different
There are also variations in how each method can be applied which can produce different results
Valuation samples

Question 27

Three considerations when making a Generic preference based measure survey?

Answer 27

Feasibility – length, complexity, method of administration. Can be assessed by response rates and completion rates
Reliability – stability over time, between raters, between location. Want the absence of bias and the minimum degree of random variation or ‘noise’
Validity - extent to which an instrument measures what it is intended to measure: content validity, face validity, construct validity

Question 28

QALYs or DALYs?

Answer 28

QALYs- more used in HICs/MICs, Mainly valued by TTO, usually answered by the general population using a preference based measure. But only 27 EQ-5D country specific tarrifs- often expensive to do so few LICs have.

DALYs- used more in LICs or MICs. Can be more difficult to link health states to.