Additional Details on Study Methodology

Online Resource 1:

Additional details on study methodology

Title: The impact of tuberculosis on health utility: a longitudinal cohort study

Journal: Quality of Life Research

Authors and affiliations

Melissa Bauer, MPH1, 2, Sara Ahmed, PhD3, Andrea Benedetti, PhD1, 2, Christina Greenaway, MD, MSc4,

Marek Lalli, MSc1, Allison Leavens, BSc1, Dick Menzies, MD, MSc1, Claudia Vadeboncoeur, MSPH1,

Bilkis Vissandjée, PhD5, Ashley Wynne, MSc1, Kevin Schwartzman, MD, MPH1

1 McGill University, Respiratory Epidemiology and Clinical Research Unit, Montreal, Canada

2 McGill University, Department of Epidemiology, Biostatistics and Occupational Health, Montreal, Canada

3McGill University Health Center, Division of Clinical Epidemiology, Montreal, Canada

4 Sir Mortimer B. Davis – Jewish General Hospital, Division of Infectious Diseases and Clinical Epidemiology, Montreal, Canada

5 Université de Montréal, Faculté des sciences infirmières – School of Nursing, Montreal, Canada

Corresponding author– Email:

Script for Standard Gamble questionnaire

In order to be consistent among patients, I will read the next section of the interview to you. It is important that I explain this section in exactly the same way to each person.

SCRIPT FOR STANDARD GAMBLE TASK

In an objective way, we would like to know what you think or your state of health in comparison to other possible health states. A health state is just a description. For example, we could describe how it is to be blind. However, it is usually very difficult to express clearly how one feels about one’s health.

To help you to express how you really feel about different states of health, including your own state of health, I will ask you to imagine living in these health sates and I will ask you to make some choices. This exercise will simply help me understand how you feel about different health states. Most of the health states I will describe are imaginary. They are not meant to describe your own health or how it will be.

These games will not affect what actually happens, and will not change your treatment. The exercise is only meant to allow you to express your preferences clearly.

Research Assistant: Record time at which you begin and end this section

We will use several cards that describe health states, and I will ask you a series of questions about them.

For each question, I will give you two choices and ask you to choose the one you would prefer for yourself.

There are no right or wrong answers, only what you think.

To make the questions easier to explain, we will use an aid similar to a game board.

We call this a Chance Board because it shows us the chance of a particular event occurring.

For each question, I will give you two choices: A or B.

Choice A will involve a risk and choice B will be certain.

Display chance board and flip to 70/30

Choice B will be a state of health that is not the best or the worst of the three descriptions on the board.

If this choice is selected, please imagine that this form of health is certain to occur.

If something is certain it is equal to a 100% chance or probability, as shown in the box here.

Point to green box

Choice A, on the other hand, is more difficult because if it is chosen there are two possible results,

perfect health and immediate death. The exercise is very dramatic!

The chances of each of these results occurring are indicated by the numbers appearing above each description

and the size of the matching colours in the circle between the numbers.

The amount of risk will be changed until we find out how much risk you will take as compared to the certain choice.

For example, for every 100 people who choose A,

70 will be perfectly healthy,

Point to 70

but 30 will die,

Point to 30

and none will know before choosing, whether they will be one of the 70 or one of the 30.

That is the chance they take.

It is important to understand that if you choose A, you have a 70% chance of perfect health and a

30% chance of dying immediately.

The pink part of the circle represents 70% and the blue part represents 30%.

Imagine that we could spin the arrow on the circle. Your state of health would depend on where the arrow lands when it stops spinning.

If it lands on pink, you will have perfect health; if it lands on blue, you will die immediately.

Your health will then be decided by chance, that is, by where the arrow stops.

To make these ideas a little clearer let’s run through a quick example.

Set chance to 90/10

Let’s imagine that you have been in an accident and you have hurt your leg.

You are in perfect health except for your leg.

When you see the doctor, he explains that you have two choices.

Imagine that Choice A is an operation and Choice B is to let your leg get better by itself.

If you let your leg get better by itself, Choice B, it is certain that you will have a limp.

You will be able to walk, but you will not be able to run.

Put the card in the green pocket

On the other hand, you can choose the operation.

The operation Choice A is risky. It doesn’t always work. If the operation does work, your leg is fixed and

you can walk and run normally.

Put the card in the pink pocket

If the operation does not work, you will have to use a cane.

Put the card in the blue pocket

Here, the chances of walking and running normally are 90 percent with a

10 percent chance of having to use a cane.

Flip to 50/50

Now I’ve changed the chances.

What are the chances that you could have the outcome in pink compared to the one in blue?

Allow respondent to answer (more likely pink, more likely blue or equal)

There is an equal chance that you can have the outcome in pink or blue.

There is an equal amount of pink and blue showing on the circle.

Move wheel to 100/0

As you can see Choice A is now a 100% chance of walking and running normally and 0% chance of

having to use a cane.

Choice B is 100% chance of walking normally and being not able to run.

Would you pick Choice A or Choice B?

Now I’ve changed Choice A to show that there is 5% chance of running and walking normally and a

95% chance of having to use a cane.

Choice B is still a 100% chance of the health described on the card.

Would you pick A or B now?

Do you understand how the Chance Board works?

Here is our first real chance question.

In Choice A, the card in the pink side will always be Perfect Health.

Insert Perfect Health card in the pink pocket

The card in the blue side will also always be Immediate Death.

Insert Immediate Death in the blue pocket

The health states for Choice B will be described on cards I will show you.

The states describe last 10 years (except immediate death).

That means that you have 10 more years to live. After 10 years, you die peacefully.

In summary, you will have to choose between A or B.

In choice A, you could have perfect health for 10 years or immediate death depending on the chance that I will vary.

If you choose A, it is chance alone that will decide whether you live in perfect health or die immediately.

If you choose B, you will definitely live with the state of health described on the card for the next 10 years and then you die.

If you think the two choices are equal, tell me and I will mark your answer.

A) Marker Health State evaluation/Own health state

Hand card to the subject

Here is the first/next/another card. Please read the description of the health state carefully.

As you can see Choice A is now a 100% chance of perfect health and 0% chance of death.

Choice B is 100% chance of the health state described on the card you just finished reading.

Would you pick choice A or choice B?

Now I’ve changed Choice A to show that there is 5% chance of perfect health and a 95% chance of death.

Choice B is still a 100% chance of the health described on the card.

Would you pick A or B now?

The board now shows Choice A to be a 95% chance of perfect health with a 5% chance of dying and

Choice B remains the same as before.

Which choice would you now prefer?

Choice A is now a 10% chance of perfect health with 90% chance of dying.

Choice B is still the same as before.

Would you prefer Choice A or B?

The board now shows Choice A to be a 90% chance of perfect health with a 10% chance of dying and

Choice B remains the same as before.

Which choice would you now prefer?

Now I have changed Choice A to 20% chance of perfect health with 80% chance of dying immediately.

Choice B is still a 100% chance of the health state described.

Which choice would you prefer?

Choice A is now an 80% chance of perfect health with 20% chance of dying.

Choice B is still the same as before.

Would you prefer Choice A or B?

The choices have now been changed so that

Choice A has a 30% chance of perfect health but a 70% chance of dying immediately.

Choice B is still the same.

Which choice would you now prefer?

Now I have changed Choice A to a 70% chance of perfect health and a 30% chance of immediate death.

As before Choice B remains the same.

Which choice would you now prefer?

Choice A has now been adjusted to indicate a 40% chance of perfect health and a 60% chance of immediate death. Would you prefer Choice A or B?

If choice A had 60% chance of perfect health and a 40% chance of death as shown on the board

would you pick choice A or B?

Now I have changed Choice A to a 50% chance of perfect health and a 50% chance of immediate death.

Choice B remains the same.

Which choice would you now prefer?

Thank you, that ends this question.

Marker health states for the Standard Gamble questionnaire

Mild health state

•You feel a little bit tired but you do not have trouble sleeping.

•Your appetite is normal. You felt sick to your stomach at first. You do not have cramps or gas.

•You are not sure that taking the pill(s) is a good idea.

•You are a little scared that you will make others sick.

•You felt scared and angry when you learned you were not well.

•You are able to do your regular activities like working and studying.

•You are seeing your family and friends as usual.

Moderate marker health state

•You feel more tired than usual, you need more hours of sleep.

•You have less appetite, feel sick to your stomach, and vomit for a few days. You also have gas or cramps.

•You are afraid of the effects of the pill(s) on your health.

•You are scared that you will make others sick.

•You feel a little angry, ashamed, or depressed because of your state of health.

•You have more difficulty in doing your regular activities. You miss a few days of work or school.

•You are seeing your family and friends less often.

Severe marker health state

•You feel very tired, you are sleeping all the time.

•You have less appetite, feel sick to your stomach, and vomit for many days. You also have cramps or gas. You feel itchy.

•You think that the pills are hurting you.

•You are very scared that you will make other sick.