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2008 Seminar Series Measuring and Analyzing Health Outcomes I-Chan Huang, PhD Lecture 2 Measurement Instrument and Method for Health Outcomes Research Department of Epidemiology & Health Policy Research University of Florida College of Medicine September 29, 2008 Announcement / Q&A

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2008 Seminar Series

Measuring and Analyzing Health Outcomes

I-Chan Huang, PhD

Lecture 2Measurement Instrument and Method for Health Outcomes Research Department of Epidemiology & Health Policy ResearchUniversity of Florida College of MedicineSeptember 29, 2008

announcement q a
Announcement / Q&A
  • Syllabus, reading materials and PowerPoint
    • Course website: www.ehpr.ufl.edu/maho
    • Use your username and password
  • Q&A
    • How can I learn about data management and analysis (e.g., software and statistical code) from this seminar series?
    • How can this seminar series help me address the research questions I encountered?
outline
Outline
  • Important domains of HRQOL/QOL
  • Measurement Instrument
  • Measurement Method
  • Note:
  • Only some instruments will be introduced in today’s
  • seminar. Please contact ICH if you need information
  • about other instruments and measurement methods.
  • Will introduce “Measurement Theory” on Oct 25.
development of pro hrqol instruments
Development of PRO/HRQOL instruments

Fig 1: Generic instruments

Fig 2: Condition-specific instruments

McHorney CA, Annu Rev Public Health 1999, pp. 309

type of health outcomes instrument

Health outcomes

Health Profile

Health states and impact on

daily functioning and well-being

Health Utility

A global value

of health states

Generic

measure

Disease- or

condition-specific

measure

Direct measure

Indirect measure

SF-36

WHOQOL-100

MOS-HIV

EORTC QLQ

TTO

SG

EQ-5D

HUI-3

Type of health outcomes instrument
domain of hrqol qol outcomes
Domain of HRQOL/QOL outcomes
  • No consensus on
    • Specific domains to be measured
  • Consensus on
    • A multi-dimensional concept
  • Agreement on primary and additional domains [Berzon R. Qual Life Res 1993]
    • Experts’ recommendations from a conference
    • Primary domains: universally important to all diseases or conditions
    • Additional domains: important to specific diseases or conditions
primary domains of hrqol qol
Primary domains of HRQOL/QOL
  • Physical functioning
    • Ability to perform daily physical activities
  • Psychological functioning
    • Level of emotional-welling, e.g., anxiety, depression, guilt and worry
  • Social functioning
    • Ability to interact with family, friends and the community
  • Perception of health status
    • Self-report of health, which may be different from health status rated by clinicians and significant other
  • Overall life satisfaction
    • Perception of overall sense of well-being
additional domains of hrqol qol
Additional domains of HRQOL/QOL
  • Neuropsychological / cognitive functioning
    • Memory, recognition, spatial skills, motor coordination
  • Intimacy and sexual functioning
    • Type, frequency, satisfaction with sexual activity
  • Pain
    • Important for cancer patients or patients with chronic conditions
  • Symptoms
    • Severity, frequency, and extent to which impacts daily functioning
  • Sleep disturbance
    • Sleep patterns and restorativeness of sleep
  • Spirituality
    • Spiritual beliefs and religious values in everyday lives and the ways of coping
  • Personal productivity
generic instrument mos sf 36v2
Generic instrument – MOS SF-36v2
  • Development
    • John E. Ware, Jr (MOS SF-36v1; 1992)
    • From 116 items of the RANDMedical Outcomes Study (MOS)
  • 8 domains (36 items: 35 +1)
    • Physical functioning (10 items)
    • Role limitations due to physical problems (4 items)
    • Bodily pain (2 items)
    • General health perceptions (5 items)
    • Vitality (4 items)
    • Social functioning (2 items)
    • Role limitations due to emotional problems (3 items)
    • Mental Health (5 items)
    • Other: health transition (1 item) – not used for scoring
  • Response category
    • Likert type: 3, 5, or 6 categories
generic instrument mos sf 36v2 cont d 3
Generic instrument – MOS SF-36v2 (Cont’d 3)
  • Alternative forms
    • SF-12 and SF-8: allowing two summary scores only
    • RAND-36 and RAND-12: matter of scoring methods
  • National norm
    • Comparing the impact of different disease groups on HRQOL outcomes
  • International projects (IQOLA)
    • 103 language versions
    • For international comparison, recommend the use of factor loadings derived from US norm as a standard to calculate domain score of different cultural groups
generic instrument whoqol 100
Generic instrument – WHOQOL-100
  • Development
    • WHOQOL Group (1993)
    • Allowing the inclusion of national-specific items
  • 6 domains (24 facets and 100 items)
    • Physical health (3 facets; 12 items)
    • Psychologicalhealth (5 facets; 20 items)
    • Level of independence (4 facets; 16 items)
    • Social relationship (3 facets; 12 items)
    • Environment (8 facets; 32 items)
    • Spirituality, religiousness & personal beliefs (1 facet; 4 items)
    • Other: overall QOL and general health (4 items)
  • Response category
    • Likert type: 5 categories
  • Language versions: 42
  • Alternative form: WHOQOL-BREF and WHOQOL-8
the same type of instrument may measure different construct huang ic qual life res 2006
Motivations

Whether the same domain (e.g., physical functioning) in the SF-36 and WHOQOL-BREF measure the same construct or not?

Methods

Factor analysis

Relative validity using different anchors: chronic conditions, health care utilization, and a global rating of QOL

Conclusions

The SF-36 and WHOQOL measures different construct

The SF-36 measures the impact of disease / treatment on daily functioning

The WHOQOL measures general satisfaction with life

The same type of instrument may measure different construct[Huang IC, Qual Life Res 2006]
the same type of instrument may measure different construct huang ic qual life res 2006 cont d 1

* Using principal component method with eigenvalue >1.0.

** Communality: proportion of a variable’s variance explained by a factor structure

The same type of instrument may measure different construct[Huang IC, Qual Life Res 2006] (Cont’d 1)
the same type of instrument may measure different construct huang ic qual life res 2006 cont d 2
The same type of instrument may measure different construct[Huang IC, Qual Life Res 2006] (Cont’d 2)
the same type of instrument may measure different construct huang ic qual life res 2006 cont d 3
The same type of instrument may measure different construct[Huang IC, Qual Life Res 2006] (Cont’d 3)

† Adjusting for age, gender, educational background, and marriage status

the same type of instrument may measure different constructs huang ic qual life res 2006
Motivations

Does the same domain (e.g., physical functioning) in the SF-36 and the WHOQOL-BREF measure the same construct?

Methods

Factor analysis

Relative validity using different anchors: chronic conditions, health care utilization and global rating of QOL

Conclusions

The SF-36 and WHOQOL-BREF measures different construct

The SF-36 measures the impact of disease / treatment on daily functioning

The WHOQOL-BREF measures general satisfaction with life

The same type of instrument may measure different constructs[Huang IC, Qual Life Res 2006]
disease specific instrument mos hiv

Adopted from

the SF-20

HIV/AIDS

-specific

Disease-specific instrument – MOS-HIV
  • Development
    • Albert W. Wu (1993)
    • Parallel to the MOS SF-36v1
  • 10 domains (35 items: 34 +1)
    • Physical functioning (6 items)
    • Pain (2 items)
    • Role functioning (2 items)
    • Social functioning (1 items)
    • General health perceptions (5 items)
    • Energy and fatigue (4 items)
    • Mental health (5 item)
    • Cognitive functioning (4 items)
    • Health distress (4 item)
    • Quality of life (1 items)
    • Other: Health transition (1 items) – not used for scoring
  • Response category
    • Likert type: 3, 5, or 6 categories
disease specific instrument eortc qlq

Functioning scales

Symptom scales

Disease-specific instrument – EORTC QLQ
  • Development
    • Neil K. Aaronson (1993)
    • European Organization for Research and Treatment of Cancer (EORTC) for international clinical trials in oncology
  • EORTC-QLQ C30: Core questionnaire
    • Physical functioning (5 items)
    • Role functioning (2 items)
    • Social functioning (2 items)
    • Cognitive functioning (2 items)
    • Emotional functioning (4 items)
    • Fatigue (3 items)
    • Pain (2 items)
    • Nausea and vomiting (2 items)
    • Global health status / QOL (2 items)
    • 6 single items (dyspnoea, loss of appetite, insomnia, constipation, diarrhea and financial loss)
disease specific instrument eortc qlq cont d

+ EORTC QLQ C-30

Disease-specific instrument – EORTC QLQ (Cont’d)
  • Response category
    • Likert type: 4 or 7 categories
  • Disease or treatment-specific “modules”, e.g.,
    • EORTC QLQ-LC13 (Lung)
    • EORTC QLQ-BR23 (Breast)
    • EORTC QLQ-H&N35 (Head & Neck)
    • EORTC QLQ-OV28 (Ovarian)
    • EORTC QLQ-CX24 (Cervical)
    • EORTC QLQ-PR25 (Prostate)
  • Each module include specific scales, directly relevant to
    • Disease-related symptoms (e.g., any pain in arm or shoulder)
    • Morbidity / side effect as a result of specific therapy (e.g., loss of hair, a dry mouth)
criticism of disease specific instruments
Criticism of disease-specific instruments
  • Over time, some domains may be not imperative due to the introduction of new treatments
    • For example, the introduction of HAART has changed the survival of HIV/AIDS (from acute to chronic disease) and led to new side effects
    • Measurement of cognitive (dis)functioning in the MOS-HIV (due to opportunistic infection or AIDS dementia) becomes less important if compared to 10 years ago
  • Other issue concerning about appearance (facial lipoatrophy due to side effect of treatment) should be included in the measurement
combined use of disease specific and generic instruments huang ic value health 2008
Motivations

Should we use generic and / or disease-specific instruments for HRQOL measurement?

Methods

Diabetes HRQOL using the SF-36 and the D-39

Validating measurement using a variety of clinical measures

1) Lab measure: HbA1c and 2-h postorandial plasma glucose

2) Complication: retinopathy, nephropathy, neuropathy, diabetic foot disorder, cardiovascular and cerebrovascular disorders

Findings

The SF-36 and D-39 were superior to each other in different regards

The SF-36 has superior discriminative validity for complications

The D-39 has superior discriminative validity for lab measures

Combined use of disease-specific and generic instruments[Huang IC, Value Health 2008]
direct and indirect health utility measurement
Direct and indirect health utility measurement
  • A single index
    • Value: 0 (worst health) through 1 (best health)
  • Direct approach (1 stage)
    • Asking respondents to directly indicate their preference for the health state as one value
    • Time trade-off (TTO), standard gamble (SG), rating scale (GS)
  • Indirect approach (2 stages)
    • Using HRQOL instruments to response their health state and then converting to one utility value using societal preference weights
    • EQ-5D, Health Utility Index (HUI), SF-6D, Quality of Well-being (QWB)
direct health utility measurement time trade off

Perfect health

1.0

Impaired health

?

Utility

0

0

Today

X

Death

t (1 yr)

Death

Time

Direct health utility measurement – Time Trade-off
  • Purpose
    • Eliciting utility by comparing the value of different health states vs. length of survival
  • Method
    • Choices (A): living in a “impaired health state” for time t (e.g., 1 year)
    • Choice (B): living in a “perfect health state” for time x
    • Varying time x or t in a systematic fashion to identify the point where subject is indifferent in preference between two scenarios
    • Health utility = x / t
direct health utility measurement standard gamble

Perfect health

Prob. p

Choice (A)

Prob. (1-p)

Dead

Choice (B)

Current

health state

(e.g., cancer)

Direct health utility measurement – Standard Gamble
  • Purpose
    • Eliciting utility by comparing different choices that account for uncertainty, including risk of death or other outcomes
  • Method
    • Choice (A): currently in a specific health state (with symptoms)
    • Choice (B): a treatment with p% of being perfect health (removing symptoms) and (1-p)% of dead
    • Varying the probabilities in a systematic fashion to identify the point where subject is indifferent in preference between Choice (A) and (B)
    • Health utility = p
indirect health utility measurement eq 5d
Indirect health utility measurement – EQ-5D
  • Development
    • EuroQol Group (1990)
  • 5 domains (5 items)
    • Mobility (1 item)
    • Usual activities (1 item)
    • Self-care (1 item)
    • Pain/discomfort (1 item)
    • Anxiety/depression (1 item)
    • Other: one visual analogue scale (0: worst health state; 100: best health state)
  • Level of health state
    • 3 levels (no problems, some problems, and severe problems)
  • Possible health states
    • 243 (= 3x3x3x3x3)
indirect health utility measurement eq 5d cont d
Indirect health utility measurement – EQ-5D (Cont’d)
  • Valuation of health states (preference weights)
    • Protocol: Measurement and Valuation of Health (MVH)
    • Population: General population in UK [Paul Dolan, Med Care 1997] and in US [Shaw JW, Med Care 2005]
    • Utility elicitation: using TTO approach for 45 health states and then extrapolating to 243 health states
    • Scoring system (US):
    • Health utility for an individual subject (e.g., health state 11223):

1-0-0-0.14-0.173-0.45-(-0.28)-0.011-0-0 = 0.506

indirect health utility measurement hui 3
Indirect health utility measurement – HUI-3
  • Development
    • George W. Torrance and David Feeny (1990)
    • Focusing on “within the skin” abilities rather than role performance and social interaction
  • 8 “attributes” (8 items)
    • Vision (1 item)
    • Hearing (1 item)
    • Speech (1 item)
    • Ambulation (1 item)
    • Dexterity (1 item)
    • Emotion (1 item)
    • Cognition (1 item)
    • Pain (1 item)
  • Level of health states
    • 5 levels: Speech, emotion, and pain
    • 6 levels: Vision, hearing, ambulation, dexterity, and cognition
indirect health utility measurement hui 3 cont d
Indirect health utility measurement – HUI-3 (Cont’d)
  • Possible health states
    • 972,000 (= 5x5x5x6x6x6x6x6)
  • Valuation of health states (preference weights)
    • Population: General population in Canada [Feeny D, Med Care 2002]
    • Utility elicitation: using RS approach for 73 health states and then extrapolating to 972,000 health states
    • Scoring system (Canada):
    • Health utility for an individual subject :

1.371 * (b1 * b2 * b3 * b4 * b5 * b6 * b7 * b8) - 0.371

crosswalk between health profile and health utility huang ic health serv res 2007
Crosswalk between health profile and health utility[Huang IC, Health Serv Res 2007]
  • Motivations
    • Can we predict health utility using health profiles?
  • Methods
    • Using MOS-HIV to predict utility score derived from the EQ-5D
take home points
Take home points
  • How to select instruments?
    • Conceptual framework of the HRQO/QOL
    • Characteristics of the population
    • Purpose of the study (e.g., decision-making at clinical or policy level)
  • Domains of different instruments with the same label (e.g., physical functioning) may measure different HRQOL/QOL concept
    • Using qualitative and psychometric approaches (esp., head-to-head comparisons) to elicit instruments genuine properties
  • Combining generic and disease-specific measures to better capture comprehensive impact of diseases on HRQOL/QOL outcomes