Chapter 15 Treatment Outcomes Across the Disablement Spectrum

Copyright © 2011 Wolters Kluwer Health | Lippincott Williams & Wilkins

Chapter 15Treatment Outcomes Across the

Disablement Spectrum

Chapter 15Treatment Outcomes Across the

Disablement Spectrum


Chapter OverviewChapter Overview

• Performing research on injured or ill patients is important to advancing the health sciences.

• The importance of selecting appropriate outcomes measures to assess in patients as their pathology progresses over time.

• Conceptual framework for the measurement of treatment outcomes.

• Delineate between disease-oriented and patient-oriented measures.

• Global and region-specific measures.

• How to choose the appropriate outcomes instruments.


Types of Outcomes MeasuresTypes of Outcomes Measures

Outcomes Measures in the Health Sciences

Disease-oriented evidence (DOE): measures that provide insight into the physiology of illness or injury

Provides information of most interest to health care providers, rather than patients

Examples: blood pressure, electromyographic activity

Patient-oriented evidence (POE): information that is subjectively self-reported by patients as opposed to gained from objective clinical or laboratory measures.

Consists of measures that are of direct interest to patients, rather than clinicians

Examples: severity of symptoms, level of function, and quality of life; also financial outcomes such as cost of health care services

POE is sometimes referred to as patient-oriented evidence that matters (POEM).


Disablement ModelsDisablement Models• The measurement of treatment outcomes in clinical

research must be built upon disablement models.

• Disablement models put forth by organizations: – Institute of Medicine– World Health Organization– National Center for Medical Rehabilitation Research

• A common foundation for all of these models is the emphasis on the psychosocial functioning of the individual patient (POE) as opposed to the physiological functioning of the patient (DOE).

• Saad Nagi (1960’s): the concept of disability as a sociological construct.

• Disability: the inability or limitation in performing socially defined roles and tasks expected of an individual within a sociocultural and physical environment. This definition is in contrast to the common perception of disability as a permanent physical or mental handicap.


Examples of Four Patients Using Nagi’s Disablement ModelExamples of Four Patients Using Nagi’s Disablement Model

Patient Demographics

20-year-old female collegiate basketball player

35-year-old male roofer 35-year-old female lawyer 70-year-old male retiree who volunteers regularly at a homeless shelter

Active Pathology Knee ligament sprain Knee ligament sprain Irritable bowel syndrome Early stage of Parkinson disease

Impairments -Knee pain-Limited knee range of motion-Quadriceps weakness

-Knee pain-Limited knee range of motion-Quadriceps weakness

-Frequent abdominal pain and bloating-Chronic diarrhea-Headaches

-Minor tremors-Slowed movements-Diminished reflexes

Functional Limitations

Unable to: -squat-kneel-climb stairs-jog-jump

Unable to: -squat-kneel-climb stairs-jog-jump

Unable to:-concentrate for extended periods of time-sit for long periods of time

Unable to:-perform upper extremity tasks without considerable shaking-walk as fast as he would like-maintain his balance as well as he previously did

Disability Unable to:-play basketball-go to classes without using crutches

Unable to:-work as a roofer-play on the floor with his young children-maintain his home garden

Unable to:-work as productively as she would like as a lawyer-participate in social activities as she would like (e.g., no movies, no dinners out)

Unable to:-Serve meals at the homeless shelter-maintain his home and yard as he would like

Quality of Life -Increased anxiety because of loss of identity as an athlete-Loss of social support from team members

-Increased anxiety because of inability to work and provide financially for his family-Depression because of inability to interact with his children as he would like to

-Increased anxiety because of inability to work as much as she would like-Extreme concern that she may not make partner at her law firm-Loss of social role in her circle of friends

-Increased anxiety about having to move out of his home because of his physical health -Loss of social support from fellow volunteers at the homeless shelter


Nagi’s ModelNagi’s Model• Active pathology: refers to the patient’s injury or illness.

• Impairment: refers to abnormality in physiological function at the site of injury. Considered DOE.

• Functional limitation: refers to limitations in actions due to the associated impairments. Represents DOE or POE depending on the context.

• Disability: operationally defined as an inability to perform normal socially expected activities due to functional limitations. Considered POE.

• Quality of life: an individual’s vitality and level of satisfaction with his or her current state of existence. Can be influenced by impairments, functional limitations, and disability. Considered POE.

• In the context of health care outcomes, this concept is referred to as health-related quality of life (HRQOL) to distinguish it from socioeconomic or interpersonal issues that may also influence an individual’s overall quality of life.


The National Center for Medical Rehabilitation ResearchThe National Center for Medical Rehabilitation Research

• The National Center for Medical Rehabilitation Research (NCMRR) is a division of the United States National Institutes of Health. NCMRR’s disablement model is similar to Nagi’s model, but it replaces “quality of life” with “societal limitations.”

• Societal limitations: refer to restrictions resulting from social policy or barriers, which limit fulfillment of roles or deny access to services and opportunities associated with full participation in society.


World Health Organization (WHO)World Health Organization (WHO)

The WHO disasblement model uses a standardized documentation system that allows clinicians and health systems to classify and quantify specific descriptors of a patient’s disability.

International Classification of Functioning, Disability and Health (ICF) model. (Reprinted with permission from World Health Organization (WHO).)


World Health Organization (WHO) ModelWorld Health Organization (WHO) Model• Patient’s health condition (at top of model): represents the patient’s

pathology in the form of a disorder, disease, or injury.

• Body functions and structures: the cause of the health condition described in terms of abnormalities.

• Activities (at the center of the model): operationally defined similarly to functional limitations in the Nagi and NCMRR models.

• Participation: involves the performance of activities in societal contexts.

• Contextual factors: (remaining portions of the model):

– Personal factors: patient’s age, sex, socioeconomic status, and previous life experiences.

– Environmental factors: physical, social, and attitudinal environments of patients; also include support and relationships, attitudes, and services and policies. These can be considered at the level of the individual or society.


Clinician Derived Measures and Patient Self-ReportClinician Derived Measures and Patient Self-ReportClinician Derived Measures

• Most health care providers routinely take measures on their patients that could be considered clinical outcomes.

– Example: core body temperature or body mass index. These measures represent DOE.

• When asked to subjectively assess their patient’s outcome or level of disability, clinicians typically rate their patient’s success substantially higher than the patients do themselves.

Patient Self-Report

• The most common type of POE comes from outcomes patients subjectively self-report on their current health status.


Global Health Measures Global Health Measures

• Survey instruments used to assess global health status typically focus on quality of life and disability.

– Multidimensional scales with questions that address physical health and emotional well-being.

Examples of common global health outcomes instruments:

• Short Form 36 Health Survey (SF 36)

• Short Form 12 Health Survey (SF 12)

• Sickness Impact Profile (SIP)

• Child Health Questionnaire (CHQ)

• Pediatric Outcomes Data Collection Instrument (PODCI)


Condition-, Region-, or Dimension-Specific Measures Condition-, Region-, or Dimension-Specific Measures

• A large number of outcomes instruments exist to assess patients with either distinct pathologies or groups of pathologies.

– These instruments are designed to address functional limitations and disabilities that are often associated with patients who have the specific injury or illness.

• Dimension-specific outcomes instruments are often designed to assess a specific physical or emotional phenomenon such as pain, anxiety, or depression.


Single Item Outcomes MeasuresSingle Item Outcomes Measures

• Having outcomes instruments with a limited number of questions is advantageous to patients, clinicians, and researchers because it eliminates redundancy in items.

• When dealing with global health, these measures essentially ask patients to answer one question: “How are you?”

• Often referred to as Single Assessment Numeric Evaluation (SANE) scores.

• Other single item tools might ask patients to judge only their level of pain or ask them if they have improved or gotten worse since their last assessment.


Choosing the Appropriate Outcomes InstrumentChoosing the Appropriate Outcomes Instrument

• Two issues are critical when clinicians and researchers select outcomes instruments to employ in clinical practice or experimental studies:

1. Matching the purpose of measurement with the instrument’s design.

2. Ensuring that the instrument’s clinimetric properties have been rigorously established.

• Be careful not to overgeneralize the utility of an outcomes instrument to populations that it was not designed to measure.

• Clinimetric properties such as reliability, validity, sensitivity to change, and internal consistency must all be assessed during the development of an outcomes instrument.


Chapter Summary and Key PointsChapter Summary and Key Points

• Disease-oriented evidence (DOE) is critical to understanding the pathophysiology of specific conditions.

• Patient-oriented evidence (POE) outcomes measures provide critical information regarding the impact that a person’s health care status has on his or her ability to function in society and his or her quality of life.

• Each disablement model provides a framework using standard terminology for the description of health status.

• Clinician-subjective reports of patient outcomes should be considered DOE rather than POE.

• Eliminating redundancy in items is an important step in developing an outcomes instrument.

• Care must be taken not to overgeneralize the utility of an outcomes instrument to populations that it was not designed to measure.

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Chapter 15 Treatment Outcomes Across the Disablement Spectrum