# Presentation: 190583

## Introduction to Effectiveness, Patient Preferences and Utilities

- Patsi Sinnott, PT, PhD, MPH
- HERC Economics Course
- May, 18, 2006

## Overview

- Brief description of cost-effectiveness analysis (CEA) and cost utility analysis (CUA)
- Key definitions
- Review of preference/utility measurement
- Review of the seven most frequently used utility measures
- Preference measurement in clinical trials
- Guidelines on selecting measures

## CEA and CUA review

- CEA compares the costs and effectiveness of two (or more) interventions;
- The _*effectiveness *_is defined by the health benefit or outcome achieved with the intervention.
- All outcomes are defined using natural units,
- Cost per avoided infection or hospitalization
- Cost per day “free of anginal pain”
- Cost per gain in Life Year (LY).

## CEA and CUA review

- Cost-utility analysis is a subset of cost-effectiveness analysis;
- Treatment effectiveness is measured in
- quantity of life and
- quality of life
- adjusted for the desirability of, or _*preference*_ for the health state achieved.

## CEA and CUA review

- CEA and CUA require all outcomes be quantified in a single scale;
- A day in hospital or an infection avoided vs.
- A  day “free of angina pain”, or day of “improved quality of life”.

## White board exercise

- What effects of treatment need to be included in a valuation of outcome?

## Whiteboard summary

- Health care interventions have impact in many dimensions of life,
- Those impacts may be more or less desirable.
- At issue is how to quantify many attributes of outcome into a single measurement scale, which includes a valuation on the outcomes.
- This valuation is defined as _*preference *_

## In CUA, the summary measure of health benefit or outcome is the QALY

- QALYs = a measure of effectiveness or health benefit;
- Includes both quality and quantity of life;
- adjusted for the desirability of, or _*preference*_ for the benefit achieved.

## The Quality Adjusted Life Year (QALY) 

- QALYs describe years of survival, adjusted for quality of life:
- 0 = death
- 1 = perfect health
- QALYs allow trade-off between length of life with quality of life:
- 1 QALY = 1 year in perfect health
- 1 QALY = 2 years with utility of 0.5

## Quantifying the QALY or outcome

- Requires:
- Description of health-related quality of life including:
- Description of all _*health states*_ expected to be experienced by patients with the condition; and
- Assessment of patient or community _*preferences*_ for each health state
- Estimation of the duration of each health state.

## Health-related quality of life

_*Quality of life*_*: broad concept, includes all aspects of life; where and how one lives and plays; family circumstances; finances; housing and job satisfaction.
_*Health-related quality of life*_*: narrower concept, that only includes aspects of life dominated or significantly influenced by  mental or physical well-being;
- Measured by _*health status measures/ or surveys.*_

- * From Ware, et al., SF-36 Health Survey Manual

## Description of all expected health states

_*Health status surveys/measures*_ – Survey of patient  perspectives about their own function, well-being and other important health outcomes.
_*Health status measures*_ describe the _*health state *_of an individual, for a specific period, or at a particular time, along various attributes of health.

## Examples of health status measures

- Generic measures:
- SF-36:  8 dimensions of  health, including physical functioning, bodily pain, social functioning and mental health.
- Disease-specific measures:
- Asthma Quality of Life Questionnaire (AQLQ)
- American Urological Association’s Urinary Bother Scale

## CUA requires a description of all expected health states, AND

- Assessment of patient or community _*preferences*_ for each health state:
- A description of all clinically meaningful _*health states*_ that patients are likely to experience (including death); and
- the valuation or _*preference*_ for each health state as defined by patients or a community sample.

## Assessment of patient or community preferences for each health state

- Only health status measures, with _*preferences/utilities*_ assessed, can be used in economic analysis;
- Only a few health status measures (generic or specific) have _*utilities*_ measured.
- In this talk, per Gold, et al recommendations, _*preferences = utilities*_

## Deriving preferences or utilities for health states

- Basic methodology:
- Surveys of patients experiencing the condition or health state of interest; or
- Surveys of a community sample.
- In both cases, individuals provide a personal reflection on the relative value of different health states experienced or described.

## Deriving preferences or utilities

- Two methods to derive preferences:
- _Direct_: individuals respond to composite descriptions of health states (their own or written descriptions)
- _Indirect_:  individuals respond to questions about separately delineated dimensions (the multiple attributes) of a health state, and a summary score or utility weight is calculated.
- Physical function
- Social functioning
- Mental health etc.

## Sample health state description

- You are able to see, hear and speak normally
- You require the help of another person to walk or get around; and require mechanical equipment as well.
- You are occasionally angry, irritable, anxious and depressed.
- You are able to learn and remember normally.
- You are able to eat, bathe, dress and use the toilet normally.
- You are free of pain and discomfort.

## Seven tools to assess preferences for health states (health utility measures)

- _Direct_ health utility measures
- Visual analog scale (VAS)
- Standard Gamble (SG)
- Time Tradeoff (TTO)
- _Indirect_ health utility measures
- Health Utility Index (HUI)
- EuroQol (EQ-5D)
- Quality of Well-Being Scale (QWB)
- SF-6D

## Direct: Visual analog scale(VAS)

- Represents the magnitude of the desirability of a single health state;
- Anchored by perfect health and death, or the worst imaginable health state.

## Direct:  Standard Gamble (SG)

- Live rest of life in current health state; or
- “take a pill (with risks) to be restored to perfect health”
- Scale represents risk of death respondent is willing to bear in order to be restored to full health.

## Direct:  Time Tradeoff (TTO)

- How much reduction in total life willing to give up in order to live in perfect health

## How to get the VAS, SG, & TTO

- A commonly used pencil and paper version of the VAS, can be obtained for free from the EuroQol Group (_[http://www.euroqol.org/](http://www.euroqol.org/)_)
- The VAS, SG, and TTO have are usually administered through interactive computer programs such as U-Titer (Summer, Nease et al., 1991), U-Maker (Sonnenberg FA, 1993), iMPACT (Lenert, Sturley, et al., 2002), and ProSPEC (Bayoumi).

## Indirect health utility measures

- Individuals respond to questions about the multiple attributes of a health state, and a summary score or utility weight is calculated
-   (the multi-attribute utility score or MAUS).
- Health utility measures vary in:
- Dimensions or attributes included;
- The size and nationality of the sample population used to establish the weights;
- Health states defined by the survey; and
- How the summary score is calculated, etc.

## Indirect health utility measures

## Indirect measures: Health Utility Index (HUI)

- 41 questions (many items can be skipped)
- can derive both HUI Mark 2 and HUI Mark 3 health utility scores.
- 8 domains of health and 972,000 health states
- vision, hearing, speech, ambulation, dexterity, emotion, cognition, and pain
- Basis of domain weights:
- Canadian community sample rated hypothetical health states
- Utility theory

## How to get the HUI

- HUI is copyrighted and can be obtained for a fee (~$3,000) from Health Utilities Inc (_[www.healthutilities.com](http://www.healthutilities.com/)_)
- For an overview of the HUI see Horsman, Furlong, Feeny, and Torrance (2003)

## Indirect measures:  EuroQol EQ-5D

- 5 questions in 5 domains of health
- Mobility, self-care, usual activity, pain/discomfort, or anxiety/depression
- 245 health states.
- Basis of domain weights:
- Past studies based on British community sample
- New US weights recently published

## How to get the EuroQol EQ-5D

- Nonprofit research can obtain the EQ-5D for free from the EuroQol Group (_[www.euroqol.org](http://www.euroqol.org/)_)
- See Dolan, Gudex, Kind, & Williams (1997) for British-based EQ-5D
- See Shaw, Johnson, & Coons (2005) for US-based EQ-5D

## Indirect measures: the QWBQuality of Well-Being Scale

- Two versions
- Original interviewer-administered
- More recent self-administered (QWB-SA)
- QWB-SA is more feasible, but still takes time
- 76 questions; 1215 health states defined;
- Includes symptoms, mobility, physical activity, & social activity
- Basis of domain weights:
- Primary care patients in San Diego, CA

## How to obtain the QWB-SA

- Contact the UCSD Health Outcomes Assessment Program (_[http://www.medicine.ucsd.edu/fpm/hoap/index.html](http://www.medicine.ucsd.edu/fpm/hoap/index.html)_) to register and obtain the QWB
- For interview-administered version see Kaplan, Bush, & Berry (1975)
- For self-administered version see Kaplan, Ganiats, & Sieber (1996)

## Indirect measures:  SF-6D

- Converts SF-36 or SF-12 scores to utilities
- When based on SF-36, uses 10 items
- When based on SF-12, uses 7 items
- 6 health domains
- physical functioning, role limitations, social functioning, pain, mental health, and vitality
- Defines 18,000 health states
- Basis of domain weights
- British community sample

## How to obtain SF-6D

- Both SF-36 and SF-12 can be obtained from _[www.sf-36.org](http://www.sf-36.org/)_ and the scoring algorithm for the SF-6D can be obtained from its developer, John Brazier.
- For converting the SF-36 into utilities see Brazier, Roberts, & Deverill (2002)
- For converting the SF-12 into utilities see Ware, Kosinski, & Keller (1996)

## Health related quality of life in clinical trials (note of caution)

- Gathering HRQoL (i.e. measuring health status) in clinical trials may have one or more purposes:
- Define the _*health states*_ that *might* be experienced during the disease progression;
- Define the _*health states*_ that _*are*_ experienced by each participant in a study;
- Establish the _*preferences*_ _*or utilities*_ for each _*health state, *_as defined by the patients with the medical condition.

## Health related quality of life in clinical trials

*Define the health states that might occur* – in order to define the physiologic stages of the condition;
*Define the health states that do occur* – to be used in modeling QALYs for a CUA, using previously established utilities for each health state experienced;
*Establish the utilities of each health state* – to compare patient with community samples and other studies.

## Health related quality of life in clinical trials (note of caution)

-   Be sure your purpose is clear, before you choose your measurement tool

## Which method to use?

- Trade-off between sensitivity and expense

## Hierarchy of methods 

- Going from least expensive to most expensive method:
- Off-the-shelf utility values
- Multi-Attribute Utility Scales (HUI, EQ-5D, QWB)
- Find values for health states identified in disease-specific survey
- Direct measure (SG, TTO)

## Off-the-shelf values

- Use utility value assigned to health state in another study
- Not all health states have been characterized
- Useful in decision modeling

## Multi-Attribute Utility Scales (HUI, EQ-5D, QWB)

- Standard surveys that are widely used
- Review published studies on psychometric properties *in the population of interest*
- MAUS may not reflect changes in health states caused by intervention (or of interest)
- May lack “responsiveness ”

## Value health states identified in disease-specific survey

- Use disease specific quality of life instrument
- Have community respondents value health states with a direct measure (SG, TTO)
- Key methods issues:
- Difficult to describing  health state to community respondent
- Difficult to establish values when there are a large number of possible health states
- Expensive, but potentially sensitive to variations in quality of life for this disease

##  Direct measure (SG, TTO)

- May be necessary if effects of intervention are complex:
- Multiple domains
- Effects not captured in disease-specific instrument
- High variance in estimates from respondents
- Reflect risk aversion, feeling about disability
- High variance = large sample size
- Not the “community value” specified by Gold et al

## Important Resources 

- Harvard Center for Risk Assessment
- _[http://](http://www.hcra.harvard.edu/)__[www.hcra.harvard.edu](http://www.hcra.harvard.edu/)__[/](http://www.hcra.harvard.edu/)_
- Brazier J, Deverill M,  Green C, Harper R, Booth A. A Review of the use of health status measures in economic evaluation. Health Technol Assess 1999;3(9).
- _[http://www.hta.nhsweb.nhs.uk/](http://www.hta.nhsweb.nhs.uk/)_
- Table of published utility weights (preferences) for different health states
- _http://www.tufts-nemc.org/cearegistry/_

## Summary

- Brief description CEA and CUA
- Key definitions
- Review of preference/utility measurement
- Review of the seven most frequently used utility measures
- Preference measurement in clinical trials
- Guidelines on selecting measures

-      QUESTIONS and COMMENTS