1 Class 1 Conceptualizing health (or its determinants) and developing one’s own conceptual framework September 29, 2005 Anita L. Stewart, Ph.D. Institute

1

Class 1Conceptualizing health (or its determinants) and

developing one’s own conceptual framework

September 29, 2005

Anita L. Stewart, Ph.D.Institute for Health & Aging

University of California, San Francisco

2

Overview of Entire Class (Epi 225)

How to critique and select good measures for your own research– Not about developing new measures

Homework – weekly– I will review and return to you each week– Basis for final paper

Discussion session (optional)– 10-11am

Focus on one concept of interest– Measurable (will need to find 2-3 measures to review)

3

Overview of Class 1

How to develop a concept before considering any measure– Health and health-related concepts are good

examples» Tend to be key outcomes in clinical research» Process is the same for any concept/measure

Consider extent to which your own concept definitions are “driven” by available, commonly used measures

4

Purposes of Assessing Health

As an Outcome: -Describe populations

-Compare groups

-Evaluate interventions

-Evaluate policy changes

-Compare health plans In Planning: -Inform decision making

-Plan health services As a Predictor: -of utilization of health services As a confounder: -Control for case-mix

5

“Health” Terminology

Health Health indicators Health status Health outcomes Clinical status Functional status Functioning and well-being Quality of life Health-related quality of life

6

Health is a Construct

A variable that is relatively abstract as opposed to concrete and is defined or operationalized in terms of observed indicators (e.g., anxiety) (Stewart and Ware, 1992, glossary)

An idea developed or constructed through informed scientific theory. Concepts that are directly or indirectly observable(Jacox, 1992) Jacox, A.K. (1992). Theory construction in nursing: An overview, in Perspectives

on Nursing Theory (2nd ed) (L.H. Nicoll, Ed.), p 348-361.

7

Question

Can you define health? What first comes to mind when you think

of the word “health”?

Health

8

Question

Does your concept/definition of health differ when you think of the health of:– your patients?

– yourself?

9

Different Perspectives?

Health

Clinician Individual

10

Question

Can you define quality of life? What first comes to mind when you think

of the word “quality of life”?

Quality of Life

11

Question

Can you imagine a study of the effect of health on quality of life?

HealthQuality of

Life

12

Question

Can you imagine a study of the effect of health on quality of life?

Health Quality ofLife

Disease Pain, well-being

13

World Health Organization Definition of Health Status

“…physical, mental, and social well-being…”

“…not merely the absence of disease or infirmity.”

WHO, 1947

14

Can Someone Have Perfect Health?

“A healthy person is someone who has been inadequately studied”

Twaddle, The concept of health status, Soc Sci Med 1974;8:29-38.

15

Perspectives on Health Individual

Clinician or Proxy

Anatomic, physiologic, biochemical “signs” X

Symptoms X X

Diagnosed physical/mental conditions X X

Severity of conditions X X

Functioning in daily life X

Well-being X

16

The Individual’s Perspective on Health

Functioning

Well-being

Health perceptions

Ability to perform basic functions and activities of daily life, usually observable

Internal, subjective feelings and perceptions (physical and emotional)

Beliefs about one’s health, known diagnoses

17

World Health Organization Definition of Health Status

“…physical, mental, and social well-being…” (individual’s perspective?)

“…not merely the absence of disease or infirmity.” (clinical perspective?)

WHO, 1947

18

Medical Outcomes Study (MOS) Framework: Physical/Mental Health From Patient’s Perspective

PhysicalHealth

MentalHealth

19

Medical Outcomes Study (MOS) Framework: Physical/Mental Health From Patient’s Perspective Physical

Mental Indicators Health

Health

20

MOS Framework: Physical and Mental Health From the Patient’s Perspective

Physical Mental

Indicators Health Health Physical functioning X Pain X Energy/fatigue X X Sleep problems X X Cognitive functioning X Psychological distress/well-being X Social activity limitations due to health X X Role limitations due to physical health X Role limitations due to emotional problems X Current health perceptions X X Stewart AL, MOS Framework, In Stewart and Ware, 1992.

21

MOS SF-36 Framework(Ware & Sherbourne, 1992)

Physical Mental

Indicators Health Health Physical functioning X Pain X Energy/fatigue (vitality) X X Sleep problems Sleep problems X X X X Cognitive functioning Cognitive functioning X X Psychological distress/well-being

(mental health) X Social activity limitations due to health

(social functioning) X X Role limitations due to physical health X Role limitations due to emotional problems X CurrentCurrent Health perceptions X X

22

Physical Health

Physicalfunctioning

Physicalfunctioning PainPain

Vitality(energy/fatigue)

Vitality(energy/fatigue)

Role –physicalRole –

physical

MOS Physical Health: Measurement Model

Health perceptions

Health perceptions

23

Defining (and Measuring) Health from Individual’s Perspective

Includes specifying

– Domains (categories, concepts)

– Content areas of each domain or sub domain

– Response dimensions

– Time frame

24

Individual’s Perspective: Domains of Functioning

Ability to perform basic functions and activities of daily life, usually observable

Domains:– Physical functioning– Role functioning– Social functioning– Cognitive functioning

Are these all part of health? Why?– As clinicians, do you care about role and social functioning?

25

Content Areas of Physical Functioning

Walking Running Climbing stairs, hills Bending, stooping Turning head Lifting, reaching, carrying Getting in/out of a chair,

car, toilet Dexterity

Climbing 1 flight of stairs

Climbing more than 1 flight of stairs

Walking 1 block Walking 3-4 blocks Walking 1 mile Kneeling Picking up an object

26

Organizing Content Areas of Physical Functioning: Example

Ambulation

Transferring

Upper extremity

Dexterity

Walking, climbing stairs

In/out of chairs, beds, cars,on/off toilet

Lifting, carrying, reaching,raising arms over head

Writing, holding utensils

27

Role Functioning Domains

Ability to fulfill various social roles

Work, student Parent Caregiver Volunteer Spouse, partner

28

Domains of “Well-Being”

Internal, subjective feelings and perceptions (physical and emotional)

Domains:– Psychological– Symptoms (e.g., fatigue, pain)– Sleep problems

29

Is physical well-being part of health?Or only physical discomfort?

Symptoms, bodily states reflecting physical discomfort (-)» Pain, discomfort» Fatigue» Sleep problems» Malaise» Other symptoms

Can physical well-being be defined? (+)» Energy?

30

Emotional Well-being

Psychological distress and well-being Positive and negative emotional/affective states

Domains (-): Domains (+):– Depression - Positive affect– Anxiety– Anger/irritability – Loneliness– Perceived stress

31

Depression

Affect(+ and -)Affect

(+ and -)Cognitions,evaluationsCognitions,evaluations SomaticSomatic Inter-

personalInter-

personal

Depression: Measurement Model

BehaviorBehavior

32

Emotional Well-being vs Mental Disorder?

Positive and negative emotional/affective states

Domains (continuum) Disorder (categorical)– Positive affect– Depressive symptoms Depression, dysthymia– Anxiety Anxiety disorder– Anger/irritability– Belonging/loneliness– Perceived stress PTSD

33

Types of Response Dimensions

State/level

Evaluative

Comparative

Agreement

Level or state of behavior or feeling - Frequency (of a symptom) - Intensity (amount of difficulty

walking)

Value attached to level or state- Satisfaction (with health)- Bothersomeness (of a symptom)

Comparison to- prior time, other persons

Level of agreement with statement

34

Possible Response Dimensions for Physical Functioning (e.g., walking)

State/level

Evaluative

Comparative

Able/unable to do Extent of limitation Amount of difficulty Need for help Speed of completing defined task

Satisfaction with ability

Walking slower than 6 months ago

35

Responses for Three Physical Functioning Measures

Do you have any trouble... walking one block… ? (AIMS)• Yes• No

Does your health limit you… in walking one block? (MOS, SF-36)• Yes, limited a lot• Yes, limited a little• No, not limited at all

Are you able to… walk one block? (HAQ)• Without any difficulty• With some difficulty• With much difficulty• Unable to do

36

Possible Response Scales for Symptoms (e.g., pain, nausea)

Level/state

Evaluative

Comparative

Had it (yes/no) Frequency Intensity/severity (usually, at its worst Amount of time, # of days had it

Extent to which bothered by it Extent of distress due to it

Extent of change in (e.g. frequency) since prior time

37

State/Level Response Scales for Sadness Items From 2 Depression Measures

Which best describes the way you felt in the past week? (Beck)• I do not feel sad• I feel sad• I am sad all of the time and I can’t snap out of it• I am sad all the time and I can’t stand it

How often have you felt “sad” during the past week? (CES-D)• Rarely or none of the time• Some or a little of the time• Occasionally or a moderate amount of time• All of the time

38

Specify Time Frame

Past:

Present:

No time frame:

Average experience over some previous time period (6 months, 3 months, 4 weeks, etc)

Current status, how they are now

Time frame not specified (assumes “in general”)

39

Example of Effect of Time Frame

In general, how would you rate your health?– Excellent

– Very good

– Good

– Fair

– Poor

40

Example of Effect of Time Frame

In the past week, how would you rate your health?– Excellent

– Very good

– Good

– Fair

– Poor

41

What are the Relationships Among Health Domains?

Are they just a lot of categories?– Different investigators define different categories

Is there some logical order among them? Very few conceptual frameworks of

relationships among health variables– Wilson and Cleary– Verbrugge and Jette

42

Conceptual Framework of Patient Outcomes: Wilson and Cleary

Wilson IB and Cleary PD, JAMA, 1995

Biologicaland

physio-logical

variables

Symptomstatus

Overallquality of

life

Generalhealth

percep-tions

Functionalstatus

The Disablement Process:Verbrugge and Jette

Diagnosesof diseases,injury,congenital,development-al condition

Abnormalitiesin specificbody systems

Restrictionsin basic physical andmental actions

Difficulty doing activitiesof daily life dueto a healthproblem

Pathology FunctionalLimitations DisabilityImpairments

Soc Sci Med, 1994;38:1-14

Based on earlier models by Nagi, the ICIDH*, and IOM**

*ICIDH – International Classification of Impairments, Disabilities, and Handicaps**IOM – Institute of Medicine

The Disablement Process: Different Perspectives


Clinical perspective Individual’s perspective

The Disablement Process


Clinical perspective Individual’s perspective

•Sometimes clinical and individual perspective differ• Knee joint impairment (scan) not correlated with pain reported by individual

The Disablement Process


Clinical perspective

Individual’s perspective

Person level Person in society

•Walk•Climb stairs

•Shop•Do laundry•Work

The Disablement Process:Trajectory of Decline






The Disablement Process:Trajectory of Decline






•Causal pathways not clear•As one moves to higher levels, factors other than pathology and impairments play greater role

49

Can you define health now?x

Health

50

Summary

Substantial variation in definitions of health and health-related concepts

Most concepts are multidimensional– Content and response dimensions are part of

definition Clarify concept definition prior to

selecting any measures

Documents

1 Class 1 Conceptualizing health (or its determinants) and developing one’s own conceptual framework September 29, 2005 Anita L. Stewart, Ph.D. Institute