Chapter 15 Treatment Outcomes Across the Disablement Spectrum

1. Chapter 15Treatment Outcomes Across the Disablement Spectrum

2. Chapter 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.

3. Types 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).

4. Disablement 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 physiologicalfunctioning 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.

5. Examples of Four Patients Using Nagi’s Disablement Model

6. Nagi’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.

7. The 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.

8. 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).)

9. World 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.

10. Clinician Derived Measures and Patient Self-Report Clinician 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.

11. 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)

12. 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.

13. Single 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.

14. Choosing the Appropriate Outcomes Instrument • Two issues are critical when clinicians and researchers select outcomes instruments to employ in clinical practice or experimental studies: • Matching the purpose of measurement with the instrument’s design. • 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.

15. Chapter 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.