Introduction to Effectiveness, Patient Preferences and Utilities Patsi Sinnott, PT, PhD, MPH HERC Economics Course May 6, 2009

Health Economics Resource Center Overview  Brief review of cost-effectiveness analysis (CEA) and cost utility analysis (CUA)  Quality of life and health-related quality of life  Review of preference/utility measurement  Review of the most frequently used preference measurement systems  Preference measurement in clinical trials  Guidelines on selecting measures

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Health Economics Resource Center CEA and CUA review  CEA compares the costs and effectiveness of two (or more) interventions;  effectiveness is defined by the health benefit or outcome achieved with the intervention.  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).

Health Economics Resource Center 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”  A day of “improved quality of life”.

Health Economics Resource Center Defining Quality of Life  Surveys and questionnaires  Domains of various aspects of life  Each combination of answers defines a composite “state” or quality of life “status” for that individual

Health Economics Resource Center Defining 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 Economics Resource Center Defining quality of life Health-related quality of life*: narrower concept, that only includes aspects of life dominated or significantly influenced by mental or physical well-being; * From Ware, et al., SF-36 Health Survey Manual

Health Economics Resource Center Defining quality of life Purpose of evaluation will determine the instrument  Quality of life measurement tool will define the broad concept of quality of life  Health-related quality of life (HRQoL) measurement tool will define an individual’s “health state” or “health status”

Health Economics Resource Center  Health status surveys/instruments – 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. Defining health-related quality of life

Health Economics Resource Center Defining health-related quality of life HRQoL instruments are used to measure  Baseline health status  Comparative health status  Effectiveness/outcomes of clinical intervention

Health Economics Resource Center Instruments to measure HRQoL Generic instruments:  SF-36: 8 dimensions of health, including physical functioning, bodily pain, social functioning and mental health.

Health Economics Resource Center Instruments to measure HRQoL Disease-specific measures:  Asthma Quality of Life Questionnaire (AQLQ)  American Urological Association’s Urinary Bother Scale  Oswestry Low Back Pain Questionnaire

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Health Economics Resource Center Whiteboard 1 What instruments have you used?

Health Economics Resource Center CEA/CUA CEA compares the costs and effectiveness of two (or more) interventions

Health Economics Resource Center CEA/CUA  effectiveness is defined by the health benefit or outcome achieved with the intervention  The effectiveness is defined by the health benefit or outcome achieved with the intervention  This effectiveness is defined by a summary measure that combines  Quantity of life, and  Quality of life, weighted by the preference for that quality of life

Health Economics Resource Center CEA/CUA The summary measure of health benefit or outcome in CEA is the QALY  includes both quality and quantity of life;  adjusted for the desirability of, or preference for the benefit achieved.

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Health Economics Resource Center Whiteboard 2 What instruments have you used (for a study of what medical conditions?)

Health Economics Resource Center 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

Health Economics Resource Center Quantifying the QALY or outcome Requires:  Description or estimation of the health states expected to be experienced by patients with the condition  Estimation of the duration of each health state  Assessment of patient or community preferences for each health state

Health Economics Resource Center Whiteboard 3 In CEA what components of health status will you need to measure ?

Health Economics Resource Center 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

Health Economics Resource Center 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 preferences/utilities measured.  In this talk, per Gold, et al recommendations, preferences = utilities

Health Economics Resource Center 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.

Health Economics Resource Center 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 (or attributes) of a health state, and a summary score or utility weight is calculated.  Physical function  Social functioning  Mental health etc.

Health Economics Resource Center Sample health state description (composite)  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.

Health Economics Resource Center Methods to assess preferences Direct method  Individuals asked to choose (declare preferences) between their current health state and alternative health status scenarios  Individuals make these choices based on their own comprehensive health state (or the composite described to them).

Health Economics Resource Center Methods to assess preferences for health states Direct Methods  Standard Gamble (SG)  Time Tradeoff (TTO)

Health Economics Resource Center 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.

Health Economics Resource Center Direct: Time Tradeoff (TTO) How much reduction in total life willing to give up in order to live in perfect health

Health Economics Resource Center How to get the SG & TTO The 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 I and II(Lenert, Sturley, et al., 2002),  ProSPEC (Bayoumi)  FLAIR1, FLAIR2, (Goldstein et al.1993)

Health Economics Resource Center Methods to assess preferences Indirect method  Individuals asked to rate preferences for separate domains of health states  Scores are aggregated to create a composite preference or utility weight for a health state

Health Economics Resource Center Sample Questions (EQ-5D) Which statements best describe your own state of health today?  Mobility:  No problems walking about  Some problems walking about  I am confined to bed

Health Economics Resource Center Sample Questions (EQ-5D) Which statements best describe your own state of health today?  Pain/discomfort  No pain or discomfort  Moderate pain or discomfort  Extreme pain or discomfort

Health Economics Resource Center The aggregate 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.

Health Economics Resource Center Indirect preference measurement systems  Individuals respond to questions about the separate attributes of a health state, and a summary score or utility weight is calculated  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.

Health Economics Resource Center Methods to assess preferences for health states Indirect Measures  Health Utility Index (HUI)  EuroQol (EQ-5D)  Quality of Well-Being Scale (QWB)  SF-6D

Health Economics Resource Center 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

Health Economics Resource Center How to get the HUI  HUI is copyrighted and can be obtained for a fee (~$3,000) from Health Utilities Inc (  For an overview of the HUI see Horsman, Furlong, Feeny, and Torrance (2003)

Health Economics Resource Center 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

Health Economics Resource Center How to get the EuroQol EQ-5D  Nonprofit research can obtain the EQ-5D for free from the EuroQol Group (  See Dolan, Gudex, Kind, & Williams (1997) for British-based EQ-5D  See Shaw, Johnson, & Coons (2005) for US- based EQ-5D

Health Economics Resource Center 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

Health Economics Resource Center How to obtain the QWB-SA  Contact the UCSD Health Outcomes Assessment Program ( ) to register and obtain the QWB  For interview-administered version see Kaplan, Bush, & Berry (1975)  For self-administered version see Kaplan, Ganiats, & Sieber (1996)

Health Economics Resource Center 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

Health Economics Resource Center How to obtain SF-6D  Both SF-36 and SF-12 can be obtained from 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 Economics Resource Center 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 Economics Resource Center 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 CEA, using previously established preferences for each health state experienced;  Establish the preferences of each health state – to compare patient with community samples and other studies.

Health Economics Resource Center Health related quality of life in clinical trials (note of caution) Be sure your purpose is clear, before you choose your measurement tool

Health Economics Resource Center Which method to use?  Trade-off between sensitivity and burden  Start with a literature search

Health Economics Resource Center Hierarchy of methods  Going from least burdensome to most:  Off-the-shelf utility values  Indirect Measures  (HUI, EQ-5D, QWB, SF-6D)  Use a disease-specific survey during the trial and transform at a later time to preferences  Direct measure (SG, TTO)

Health Economics Resource Center Off-the-shelf values  Use preference weight determined in another study for health state of interest  Not all health states have been characterized  Useful in decision modeling

Health Economics Resource Center Indirect measures (HUI, EQ-5D, QWB, SF-6D)  Standard surveys that are widely used  Review published studies on psychometric properties in the population of interest  May not reflect changes in health states caused by intervention (or of interest)  May lack “responsiveness ”

Health Economics Resource Center Using disease-specific survey  If consequences of the treatment or disease are not captured with a generic measure  Use disease specific quality of life instrument  Have community respondents value health states with a direct measure at a later time

Health Economics Resource Center Using disease-specific survey  Key methods issues:  Difficult to describe 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  Often used in addition to generic measure

Health Economics Resource Center Direct Method (SG, TTO) Direct Method (SG, TTO)  May be necessary if effects of intervention are complex:  Multiple domains  Effects not captured in disease-specific instrument

Health Economics Resource Center  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 Direct Method (SG, TTO) Direct Method (SG, TTO)

Health Economics Resource Center Important Resources  Harvard Center for Risk Assessment  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).  Table of published utility weights (preferences) for different health states

Health Economics Resource Center HERC PL Sinnott, Joyce, JR, Barnett, PG. Preference Measurement in Economic Analysis. Guidebook. Menlo Park, CA. VA Palo Alto Health Economics Resource Center

Health Economics Resource Center QUESTIONS and COMMENTS QUESTIONS and COMMENTS