# Presentation: 134394

## The ICF and statistics on disability and health

**The ICF and statistics on disability and health**

*Classification, Assessment, Surveys and Terminology (CAS/EIP)*
*World Health Organization*
*Geneva*
*T Bedirhan Ustun and Marguerite Schneider*
**Washington City Group on Measurement of Disability ****Washington D C, **
**18 - 20 February 2002**

**Notes:**
Previously, countries mainly reported mortality statistics on the basis of the international classification of diseases (ICD) system. This approach was useful to identify life expectancy and causes of death, but the data collected gave no further indication of health status (among the living population). Additional information on population health was needed. Resolution WHA29.35 approved the supplementary classification of impairments and handicaps. As a result, WHO issued in 1980 a tool for the classification of the consequences of disease, namely the International Classification of Impairments, Disabilities and Handicaps (ICIDH). It was field-tested in several countries and a revision process was begun in 1995 to address, inter alia, the need to use the classification as a framework for the reporting of the health status of populations. Over the subsequent five years, several WHO collaborating centres and both governmental and nongovernmental organizations have taken part in the revision and field-testing of successive versions. With the revisions, the title has evolved, and it is now proposed to call it the International Classification of Disability and Health. As it currently stands, ICIDH is a complementary member of the WHO family of international classifications. Whereas ICD provides the codes for mortality and morbidity, ICIDH provides the codes for health states of individuals.
 ICD: the International Statistical Classification of Diseases and Related Health Problems. The Tenth Revision (ICD-10) was published in 1992.
 The Beta-1 version issued in 1997 was entitled ICIDH-2: International Classification of Impairments, Activities and Participation. For the 1999 Beta-2 version the title was changed to ICIDH-2: International Classification of Functioning and Disability. The proposed new title is ICIDH-2: International Classification of Disability and Health. The acronym ICIDH, used as a generic term to refer to the classification, is retained for historical reasons.

## Slide 2

## UN Disability rates

**Wide inter-country variation**
**60 fold difference (0.2 - 30%)**
** **
**Reliability**
**unknown - not measured**
**Construct validity**
**not sure what is being measured **

## Possible explanations for between country variations 

**real differences**
**levels of development**
**different environments**
**population age structure**
**time of data collection**
**Methodological differences**
**Census vs surveys**
**different concepts of ‘disability’**
**different domains**
**different questions**
**different levels of severity**

## Slide 5

## Life expectancy

**Measuring number of years people are expected to live based on mortality statistics in countries**
**Reliability: Good**
**different measurements give similar results**
**Differences indicate real and expected differences between countries**
**developed vs developing**
**responsive to health interventions**
**internationally recognised consensus measure**
**used in different indices: Human development index; Health system performance**
**Need indicators with similar properties for disability**

## Slide 7

## Life expectancy and % disabled

**No relationship between country differences in % disabled and life expectancy**
**disability measure lacks face validity**

## LE and % disabled (2)

**Disability levels cannot be explained by other covariates, such as**
**age structure**
**development level**
**life expectancy**
**education level**
**economic level**
**other contextual variables...**
**as disability % goes up, more face validity**
**Current disability statistics are not clear**

## What is wrong with disability statistics

**Not holistic **
**focus more on the physical (vision, hearing and mobility and severe mental handicap) than mental health **
**not multi-dimensional**
**usually activity limitation or impairments or mix**
**very limited in terms of participation and environmental factors**
**not comparable mainly because not using common conceptual framework**

## What is wrong with disability statistics (2)

**poor reliability and validity - even if measure is reliable cannot compare if not same conceptual framework**
**traditionally, used set definitions of disability as input (blind, deaf, physically disabled, etc. ) - no measure of individual domains within each category**
**threshold is set at outset and cannot be changed and need new set of data for each purpose**

## Disability and health surveys: Same and different

**Health surveys**
**health condition**
**cause of health condition**
**risk factors**
**prognosis**
**health system interventions**
**satisfaction**

**Disability surveys**
**health condition**
**level of functioning at body, person and societal level**
**assistance required**
**other facilitators and barriers  **
**satisfaction**

## WHO World Health Survey

**Uses ICF domains**
**these domains are based on international consensus**
**domains lend themselves to empirical validation for cross-population comparability**
**calibration tests**
**vignettes**
**20% of domains explain 80% of variance in health level**
**summarise data into summary measures of population health**

## Level of health across 6 core ICF domains

**6 core ICF domains used to measure level of health**
**Cognition****	****	*****understanding - communication***
**Mobility****	****	*****moving around***
**Self-care****	****	*****washing, toileting, eating***
**Affect****	****	*****depression, anxiety***
**Pain****	****	*****physical bodily pain***
**Usual activities****	*****housework, work, school***
**Measured in standard surveys**
**WHO multi-country Survey Study in 61 countries 2000-2001**
**Adjusted for self-report bias**

## Level of health across 6 core ICF domains (2)

**Aggregate the level across whole population**
**Cross country comparisons**
**Less variation than current disability statistics because:**
**identical concepts being measured**
**same method of measurement**
**reliability measured and ensured**
**self-report bias is adjusted for**

## Average levels of health

- (yrs lived with disability expressed as fraction of total number of years)

## Using ICF for both disability and health statistics

**According to ICF, disability and health are defined across the same domains**
**Surveys assess the same set of domains**
**questions measuring the same thing at different levels**
**impairment**
**capacity & performance**
**Key issue is the definition of a threshold level for which you define any disability for a given domain**
**Threshold is arbitrary and can be set at different levels for different purposes**

##     ICF Checklist 

**One component- One page**
**Salient Categories (169 out of 1494) at-a-glance**
**	****-Impairments with Body Functions**
**	****-Impairments with Body Structures**
**	****-Capacity and Performance in     Activity and Participation Domains**
**	****-Environmental Factors**
**	****-Other Contextual information**
**Additional notes**
**Available for Clinicians**

## WHO Disability Assessment Schedule - WHO-DAS II

**Validated across number of countries and conditions**
**based on ICF domains**

## What is disability?

**Outcome of interaction:**** **
**person’s health condition + contextual factors = DISABILITY**
**This outcome of disability can be described at 3 levels:  **
**body (impairment of body function or structure)**
**person (activity limitations measured as capacity) **
**society (participation restrictions measured as performance)**
**Plus description of contextual factors - personal and environmental**

**Notes:**
Disability is the outcome of the interaction between a person’s health condition and contextual factors. 

This outcome can be described at three levels of functioning:
1. The body level as an impairment of body function or body structure

2. The person level as an activity limitation measured using the construct of capacity in the information matrix

3. The society level as a participation restriction measured using the construct of performance in the information matrix

In addition the full description of the outcome requires description of the contextual factors, including both personal and environmental factors.  

## Body functions and structures 

**Body functions**** (b - codes) are the physiological functions of body systems (including psychological functions)**
**Body structures**** (s -codes) are anatomical parts of the body such as organs, limbs and their components **
**Impairments**** **
**are problems in body function or structure as a significant deviation or loss**
**are the manifestation of an underlying pathology**
**can be temporary or permanent; progressive, regressive or static; intermittent or continuous; slight through to severe**

## Activities and Participation 

**Activity**** is the execution of a task or action by an individual**
**Participation**** is involvement in a life situation**
**Activity limitations**** are difficulties an individual may have in executing activities**
**Participation restrictions**** are problems an individual may experience in involvement in life situations**

## Constructs for A and P: Capacity

**‘****Just me’ - inherent ability**
**person’s ability to execute a task or action **
**notion is independent of environment  **
**measurement within an environment (standard environment) **
**compared to individual without a similar health condition **

## Constructs for A and P: Performance

**‘****Me plus my context’ - outcome **
**what a person does or what happens in his or her current environment **
**notion is dependent on environment - **
**when the environment is facilitating, the outcome is improved functioning;                                                                                              **
**when the environment is hindering, the outcome is worsening disability. **
**compared to individual without a similar health condition **

## Environment 

**ICF Part 2: Contextual factors has two components:**
**personal factors**** ****(not classified in ICF)**
**environmental factors**** ****(ICF EF Section)**
**Environmental factors (EFs) are ****external factors**** that make up the physical, social and attitudinal environment in which people live and conduct their lives**
**EFs form part of both the immediate and distant or background environments**

**Notes:**
The ICF Part 2: Contextual factors has two components:
personal factors (not classified in ICF)
environmental factors (ICF EF Section)

Environmental factors (EFs) are external factors that make up the physical, social and attitudinal environment in which people live and conduct their lives. 

EFs form part of both the immediate and distant/ background environments. The same environmental factor can operate as a facilitator or barrier within a person's immediate environment as well as within the background environment. 
An example is that of attitudes as experienced by an individual as well as a background factor influencing policies. 

## Environment and functioning

**Body Function/Structure and Activity: **
**independent of E for definition**
**manifestation of latent health condition *****may***** occur through impact of EFs  **
**aggravation of existing impairment or Activity Limitation**
**measurement of function, structure or activity within an environmental context **
**Participation:**
**environment is integral to the definition**
**description of environmental factors is part of description of participation**
**changes in environment causes changes in participation**

**Notes:**
Environmental factors have a fundamental link to the components of functioning and the outcome of disability as an impairment, activity limitation and participation restriction.  
Body function/structure and activity: two aspects
Firstly, Body function and structure as well as Activity are independent of environment for their definition. However, the manifestation of a latent health condition may occur through impact of environmental factors. Examples of this would be an underlying condition of hay fever, with symptoms that only manifest in an environment with high pollen count; and the health condition of night blindness that only manifests itself when there is a lack of light, thus causing difficulty in reading. 
Secondly, while the definition of body function and structure and activity is independent of environment, the measurement of these is always within an environmental context that can be described using the environmental factors framework. Activity is measured using the construct of capacity.
Participation:
The environment is integral to the definition of participation, and, therefore, the description of environmental factors must be part of describing the participation of a person (measured as performance).
An example of this would be a participation restriction in mobility occurring only in inaccessible buildings for person with activity limitations in walking.  The participation restriction does not occur when the buildings are accessible. 

## The added value of ICF...

**comprehensive approach for describing functioning at body, person and societal level.**
**common framework for****  **
**needs assessment **
**selection of a targeted population (e.g. eligibility for **
**	****benefits)**
**comparison within and across different people**
**monitoring and evaluation within and between **
**   ****interventions**
**prioritisation of interventions**
**common language for communication**

## Conclusion on ICF

**Descriptive tool (not evaluative)**
**provides common framework**
**allows for clear continuum: health and disability statistics use the same framework**
**provides profile of individual domains**
**allows different thresholds for same data set**

## Conclusions: general 

**Current international ‘Disability Statistics’ are problematic**
**Census and survey data could be expressed in ICF terms, thereby:**
**increasing conceptual clarity**
**reliability**
**comparability**
**ICF domains as basis for health and disability statistics**

## Contacting WHO

**www.who.int/classification/icf**

**Contacting WHO**

## How can we include the information matrix and EFs?

**Wording and sequence of questions**
**‘****What difficulty do you have in....?’**
**‘****What happens in your usual/current environment?’**
**‘****What features of the environment make it easier or more difficult for you to...?’**
**Cognitive testing of what context people have in mind when reporting difficulties**
**Ask about a wider range of domains and environmental factors**** **
**involvement in civil society, friendships, caring for others, etc.**
**attitudes, natural environment, design of land areas, systems and policies, services such as housing, political, legal, etc.   **

## Disability and health surveys: common ground

**Health of a population**
**List of domains**
**Vision****	****	****	****	****Communication**
**Hearing****  ****	****	****	****	****Mobility and dexterity**
**Speech                   ****	****	****	****Self-care **
**Digestion                 ****	****	****Usual activities**
**Bodily excretion   ****	****	****	****Social functioning**
**Fertility                  ****	****	**
**Skin & disfigurement****	****	**
**Breathing                ****	****	**
**Pain                       ****	****	**
**Affect                      ****	****	**
**Sleep                      ****	****	**
**Energy/vitality       ****	****	**
**Cognition               ****	**
**	**
**                                   ****	****	**