115147Setting up a cohort study of functioning: From classification to measurement

Prepared for submission to Journal of Rehabilitation Medicine, Special Issue on Describing

the lived experience of persons with spinal cord injury

First author: Birgit Prodinger1,2,3

Second author: Carolina Saskia Ballert1,3

Senior author: Alarcos Cieza1,4, 5

for the SwiSCI Study Group

1 Swiss Paraplegic Research (SPF), Nottwil, Switzerland2 ICF Research Branch in cooperation with the WHO Collaborating Centre for the Family of

International Classifications in Germany (at DIMDI), Nottwil, Switzerland3 Department of Health Sciences and Health Policy, University of Lucerne and SPF, Nottwil,

Switzerland4 Faculty of Social and Human Sciences, University of Southampton, UK5 Public Health and Health Services Research, Department of Medical Informatics, Biometry

and Epidemiology (IBE), Ludwig-Maximilians-Universität (LMU) Munich, Germany

1

Abstract

Objective: Cohort studies constitute a study design most suitable for the collection of

population-based longitudinal data to track people’s health and functioning over time.

However, describing and understanding functioning in its complexity with all its determinants

is one of the biggest challenge clinicians and researchers face.

Design: This paper focuses on the development of a cohort study on functioning by outlining

the relevant steps and related methods, and illustrates these by drawing upon the Swiss Spinal

Cord Injury Cohort Study (SwiSCI).

Subjects: NA

Methods and Results: The first step in setting up a cohort study is to specify the variables to

be included, that is, what to assess. The International Classification of Functioning, Disability

and Health (ICF) is most valuable in this process. Once it has been specified what to assess,

the second step is to identify how to assess the specified ICF categories. Existing instruments

and assessments can then be linked to the ICF.

Conclusion: The methods outlined in this paper assure that the development of a cohort study

builds upon a comprehensive perspective of health as operationalized through functioning as

conceptualized and classified in WHO’s ICF, and yet remains efficient and feasible to be

administered.

Keywords: International Classification of Functioning, Disability and Health (ICF),

standardized reporting, cohort study, epidemiology

2

Introduction

Understanding health in its complexity with all its determinants is one of the biggest

challenges that clinicians, health researchers and policy makers face. It requires taking into

consideration the interaction of a health condition with its related impairments and the

person’s environment, which together yield the experience of living with a given health

condition.. Cohort studies constitute a study design most suitable for the collection of

population-based longitudinal data to track people’s health over time, to identify risk groups

and set intervention targets to guide the development of health policies and programs, and to

monitor them (1). Common outcomes of cohort studies are morbidity, including the incidence

and prevalence of a health condition, and mortality (2). Functioning, which according to

World Health Organization’s (WHO) International Classification of Functioning, Disability

and Health (ICF) is the operationalization of health from a comprehensive perspective (3, 4),

is also a relevant outcome in cohort studies (5) but has not as yet received as much attention.

Functioning is an umbrella term for the interaction of a health condition, including

impairments of body functions and structures of a person, with personal and environmental

factors, the outcome of which is the activities and participation of a person (3). Data on

functioning can be derived directly from individuals by conducting clinical tests, interviews or

surveys, or indirectly through existing registries or hospital and health statistics. Each of

these methods has its merit. Regardless from which source the information is derived, a

commonly agreed upon framework is needed that provides the conceptual foundation to

facilitate the development of a new cohort study on functioning, while at the same time is

designed to assist the comparability of existing data sets.

WHO’s ICF offers an internationally agreed-upon standard for describing and monitoring

functioning. It has been endorsed by all WHO member states (3). As shown in Figure 1, the

ICF is structured into two parts, each of which further specified into two components, and

together classify more than 1450 ICF categories. Because of its structure and the

exhaustiveness of its classifications, the ICF is promising as a conceptual framework to guide

the selection of relevant variables within each of the specified components. ICF categories

have not been developed as operational variables but rather as units of a mutually exclusive

and cumulatively exhaustive classification of domains of functioning, together representing a

universal human experience. Hence, the ICF does neither specify which ICF categories of a

3

component are the most relevant to describe, or in which context, and certainly does not

determine how to measure those that are relevant. The question remains, therefore, how to

proceed from the complex phenomena of functioning to operational variables for a cohort

study designed to describe and understand functioning over time.

[Figure 1 to appear here]

This paper tackles this challenge by outlining steps and related methods in the development of

a cohort study on functioning, and by illustrating these steps and methods by drawing on the

example of the Swiss Spinal Cord Injury Cohort Study (SwiSCI). SwiSCI, we believe, can

serve as a model for this purpose as it is one of the few cohort studies that has as its main

objective that of describing the functioning of people living with a health condition over their

life span and across the continuum of care (6).

Methods

Step 1: Specifying relevant aspects of functioning to be considered in a cohort study on

functioning

The first step in setting up a cohort study on functioning is to determine the domains within

each of the components of the ICF most relevant for a given clinical population. This

determination serves as the foundation for specifying the variables to be included in the study,

in order to question what to assess. The comprehensiveness of the ICF is its strength, although

this same comprehensively makes it impractical for use in routine practice or research. A

systematic approach is needed to determine the ICF categories that are most relevant in a

given setting or context. In response to this challenge, ICF Core Sets have been developed.

These are sets of ICF categories that have been identified by means of a multi-phase and

multi-method, international consensus process for certain health conditions (7). A

comprehensive and brief version of the core sets exists for each health condition for which an

ICF Core Set has been developed. Comprehensive ICF Core Sets contain a number of ICF

categories necessary to be sufficiently comprehensive in describing the typical spectrum of

functioning of a person with the given health condition. Brief ICF Core Sets are a selection of

ICF categories from the corresponding Comprehensive ICF Core Set and are recommended

4

for use in clinical studies (8). Each ICF Core Set can be complemented with any category of

the ICF as deemed relevant in a given context.

There are two further points worth mentioning regarding the ICF Core Sets. First, their

development aimed to identify the most relevant ICF categories to be consistently described

and reported in a given health condition based on what we know from the literature and from

experts, including patients themselves, across the world (7). While these ICF categories are

definitely significant for a comprehensive description of functioning, we also need to make

sure that the ICF Core Sets contain those ICF categories that make it possible to best describe

variations in functioning within and between individuals and populations. In response to this

challenge, additional statistical sets have been developed that build upon and are

complementary to the existing ICF Core Sets. Statistical sets are build based on regression

models using self-reported health and clinician’s reported health as dependent variable and

the ICF categories from the comprehensive ICF Core Sets as independent variables (9). The

ICF categories found to have most explanatory power of health in a given health condition

can then be added to the ICF categories that were selected from the literature and expert

opinion during the multi-stage consensus process in the development of ICF Core Sets.

Second, the health condition-specific focus of ICF Core Sets has limited value for ensuring

comparability with the general population, as well as with other clinical populations. To

answer this problem, ICF Generic and Rehabilitation Sets have been developed

psychometrically. The ICF Generic Set contains 7 ICF categories that have been shown

statistically to best describe functioning in people across health conditions and the general

population (10). When the focus is specifically on clinical populations, these ICF categories

can be complemented with 23 ICF categories into a more extended ICF set of 30 ICF

categories which is referred to as the ICF Rehabilitation Set (11). These additional 30 ICF

categories best describe functioning across various clinical populations and across the

continuum of rehabilitation care from acute, to early post-acute, and long-term care.

To summarize, the ICF Generic and Rehabilitation Sets contain the ICF categories most

relevant to compare information across the general and clinical populations. ICF Core Sets for

a specific health condition complement the ICF Generic and Rehabilitation Set with ICF

categories most relevant to be described in a specified clinical population. Furthermore, a

statistical set adds additional relevant ICF categories by specifying those ICF categories

needed to best describe variations in functioning within a given health condition.

5

Subsequently, any additional ICF category relevant in a given context or for a particular

patient can be added from the universe of the ICF.

There is one further consideration worth mentioning. ICF categories are hierarchically

ordered with increasing levels of specificity as illustrated in Figure 1, with a more detailed

illustration for ICF category d440 Fine hand use. This is a second level ICF category.

Categories at the 3rd level are more granular still. The majority of ICF categories contained in

the ICF Core Sets are on the 2nd level. But, regardless of the level in the hierarchy, to be

transparent concerning the actual variables that need to be considered in a cohort study, it is

important to further specify these 2nd level categories before actually deciding how to assess

them. Category specification refers to the identification of the particularly relevant aspect of

an ICF category to assess. In the case ofb152 Emotional functions, for example, this would be

the 3rd level categories of be anxiety, depression, or fear. The proposed methods therefore

require a further systematic literature review of completed and ongoing studies and

international recommendations, in order to determine the level of specificity that is

appropriate for the data elements in clinical research and practice specific to the area of study

(12).

Step 2: Identifying how to assess relevant aspects of functioning

Once it has been specified what to assess, the second step is to identify how to assess the

specified ICF categories. Given the number of instruments and assessment tools that have

been developed over the decades, there is no need to develop new instruments but rather to

link existing instruments and assessments to the ICF. ICF linking rules have been developed

to guide this linking process (13, 14). Based on extensive linking experience, further

refinements have been proposed to the ICF linking rules originally published in 2005 (15).

These refinements deal with two issues. First, instruments adopt different perspectives using

the same category. For instance, one can ask about the difficulties in getting dressed, the

person’s satisfaction with his or her ability to get dressed, or the assistive devices needed for

getting dressed. Secondly, instruments and assessment tools deploy various approaches for

quantifying the responses of an item, for example in terms of intensity of problems in getting

dressed or the frequency of personal assistance needed. The perspectives adopted in existing

instruments and the approaches deployed for quantifying the information are all legitimate

and valuable, of course, but for data comparability it is important to clarify not only whether

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two items link to the same ICF category, but also from which perspective the information is

asked and how it becomes quantified (15).

Once relevant items, sub-scales, or full instruments have been specified, the researchers need

to reflect on the efficiency and feasibility of the instrument, as well as comparability with

other sources of information to finally decide which to use (16). Efficiency refers to the

number of items of an instrument that can be linked to a specified ICF category based on the

selected Core Sets and the total number of items in an instrument. The instrument is most

efficient – or the value is closest to 1 – if most of its items link to an ICF category that has

been selected as relevant to be considered in a cohort study on functioning. Feasibility refers

to practical considerations such as the costs and legal aspects associated with administering a

certain instrument, as well as the acceptability of certain questions in a given (sub-)

population and length of an instrument. Comparability with other studies or routine clinical

practice is important as it influences whether the study findings can be later pooled or

compared with existing practices in research and practice. To make the final determinations of

which items, sub-scales or instruments to use, researchers need to balance the burden on

respondents with the comprehensiveness and comparability of the information gained.

Respondents’ burden needs to be minimized as much as possible, while comprehensiveness

and comparability maximized to the best possible extent (16).

Development of SwiSCI as a case in point

The methods described in this paper have been followed in the case of SwiSCI. Here we

present examples from SwiSCI development that focus on the body functions and structures,

and activities and participation. The full materials can be requested from the authors.

Step 1: Specifying aspects of functioning to be assessed in SwiSCI

The ICF Generic and Rehabilitation Sets were the starting point for specifying the variables to

be assessed. Subsequently, SCI-specific Brief ICF Core Sets were identified, one for the early

post-acute (17) another for the long-term (18) context. In addition a statistical set for SCI has

been developed (11). (It is worth mentioning, that the latter set was only developed after

SwiSCI was launched, so that the categories in the statistical set were not considered in the

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first survey wave but will only be in the future.) Table 1 outlines the list of ICF categories

contained in SwiSCI and lists the ICF set from which they derived from.

[Table 1 to appear here]

To go from ICF categories to operational variables, the ICF categories were further specified

based on a literature review in PubMed, recommendations for data sets by the International

Spinal Cord Society (ISCOS, 19), and a platform focusing on rehabilitation evidence in SCI

(20). By following this process the category specifications for, e.g. b152 Emotional functions,

became anxiety and depression and for b280 Sensation of pain, shoulder pain and pain in

general (Table 2, column 1 and 2). The details of the literature search and analysis have been

published previously (21). [Table 2 to appear here]

Step 2: Identifying how to assess relevant aspects of functioning in SwiSCI

Based on the category specification for each ICF category, (sub-) scales or (items of)

instruments were identified that are commonly used to assess the respective categories. The

second part of Table 2 (column 3 and 4) lists all the scales and instruments that resulted for

e.g. b152 Emotional functions and b280 Sensation of pain. The identified instruments were

linked to the ICF as exemplified for the Spinal Cord Injury – Secondary Conditions Scale

(SCI-SCS) in Table 3. The sub-scales and instruments linked to b152 Emotional functions and

b280 Sensation of pain constitute a link between category and an entire sub-scale or

instrument, while in the SCI-SCS single items link to different ICF categories.

[Table 3 to appear here]

Once the ICF categories that need to be translated into operational variables were specified

and the linking tables of each instrument developed, the issue of efficiency, feasibility, and

comparability were considered. For b152 Emotional functions and its specification with

anxiety and depression the Mental Health Sub-scale of the SF-36 was chosen. This scale was

efficient as it covers items on anxiety and depression. Given that it is widely used, it ensures

comparability across the SCI population as well as between individuals and populations

experiencing other health conditions and the general population. Furthermore, the number of

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items in its self-report administration mode makes it feasible to use in the SwiSCI community

survey.

To ensure efficiency, feasibility, and comparability, it is not only important to look both at

each identified ICF category in isolation and categories. For instance, b280 Sensation of pain

is in SwiSCI by an item of the SCI-SCS as well by selected items of the International SCI

Basic Pain Data Set. The SCI-SCS with its 16 items would not be efficient for

operationalizing the single ICF category b280 Sensation of pain as only one out of its 16

items links to this ICF category. However, when looking at the SCI-SCS and its linking across

ICF categories, it becomes obvious that the instrument is efficient for SwiSCI as all except of

one item link to an ICF category specified in the relevant ICF Sets considered in SwiSCI

(Table 3). Only 4 out of the 16 items were not linked to any ICF category of the body function

component identified as relevant for describing functioning of people with SCI. In fact, this

single instrument covers 14 out of 30 identified body function categories.

Discussion

This paper outlines relevant steps and related methods for the development of a cohort study

on functioning based on the ICF. It specifies in particular how to go from the complex

phenomena of functioning to specifying operational variables for consideration in a cohort

study on functioning. The steps and methods outlined in this paper assure that the

development of a cohort study builds on the comprehensive perspective of health, as

operationalized by functioning in WHO’s ICF, and yet remains efficient and feasible to be

administered. Using the ICF as a foundation in the development of a cohort study on

functioning ensures that the operationalization of a comprehensive perspective on health in

the specification of what aspects to consider in a given study. At the same time, the methods

outlined here do not ignore existing instruments or common practice, but rather try to

integrate them into a comprehensive frame of reference. This approach ensures

comprehensiveness and coverage across existing instruments and prevents researchers from

selecting variables because of convenience from existing instruments or common practice.

Furthermore, the comparability with existing clinical and research practice is assured as the

operationalization of a single ICF category builds upon existing scales and instruments.

The challenge of setting up a cohort study on functioning comes with creating a

comprehensive yet parsimonious set of categories and related items. The ICF Core Sets

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ensure comprehensiveness as they encompass a broad range of ICF categories across all

components relevant to human functioning, and thus relevant in an epidemiology of

functioning. At the same time, the international scientific community recommends techniques

for assessing some of these ICF categories. For example, the International Spinal Cord

Society (ISCOS) has proposed standard variable names for SCI data sets in order to foster the

integration of clinical and research data. Data sets have been developed for specific domains

such as pain, bowel function, urodynamic, and cardiovascular functions (19). Each of these

data sets contain questions reflecting, as in pain, severity and frequency of pain, pain location,

and quality of pain. In developing a cohort study such as SwiSCI, which captures relevant

aspects of functioning across all components of the ICF, it is important to ensure

comparability with these existing sets by identifying a succinct standard variable set, while

trying to facilitate the development of specific modules or nested projects that allow studying

a phenomenon or domain in greater depth. Such an approach makes it possible to establish a

comprehensive survey, aligned with international standards and recommendations by relevant

international communities, which can also be feasibly administered.

In the specification of which items to choose, for each component of the ICF, some challenges

were identified above and these need to be tackled by the study team. The context of a

community survey shapes the administration mode, but not all ICF categories can be easily

assessed with this or any other approach. In SwiSCI Community Survey, clinical or diagnostic

tests were not feasible to administer, which limited the items that could be used to those

suitable for self-report. Some ICF categories items serve as indicators for impairments, while

not assessing them directly. For instance b810 Protective function of the skin was and used as

a proxy for the very specific SCI issue of decubitus. Furthermore, it is worth recalling that one

of the guiding principles in specifying the assessment of the domains included in SwiSCI was

that of ensuring compatibility and comparability with existing practice in SCI. The SCIM

instrument is a widely used clinician-administered instrument in SCI to assess the

independence in activities of daily living of people with SCI. But to be able to use this

instrument in the SwiSCI community survey, a self-report version needed to be developed

(22, 23).

The steps in the development of the data items for SwiSCI answers the call of both the World

Report on Disability (24), and the International Perspectives on Spinal Cord Injury (25), for

strengthening comparable data. Using the ICF as a foundation to specify what is important to

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be considered and being transparent in the methods to specify the relevant categories and their

translation into operational variables is highly valuable as it makes it possible to establish

qualitative and quantitative comparability with any other study. Having the ICF categories of

the ICF Generic and Rehabilitation Sets included in the variable set facilitates comparability

across health conditions and across settings in the future. These ICF categories can be seen as

the minimum standard or common denominator most relevant for comparability of

functioning information across clinical (sub-) populations, across settings along the

continuum of care, and across countries.

Conclusion

In this paper we outlined the conceptual and methodological framework for setting up a

cohort study on functioning that is – at the same time – designed to assist the comparability

with data from existing data sets. The specific steps toward specifying what to assess in

rehabilitation practice and research, and how to assess the specified domains using SwiSCI as

a case in point to illustrate the methods. The approach outlined in this paper facilitates

bridging classification with existing approaches and methods of assessment. As such, it

facilitates, on one hand the standardized reporting, and on the other comparability with

existing clinical practice and research.

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Acknowledgements

This study has been financed in the framework of the Swiss Spinal Cord Injury Cohort

Study (SwiSCI, www.swisci.ch ), supported by the Swiss Paraplegic Foundation.

The members of the SwiSCI Steering Committee are: Xavier Jordan, Bertrand Léger

(Clinique Romande de Réadaptation, Sion); Michael Baumberger, Hans Peter Gmünder

(Swiss Paraplegic Center, Nottwil); Armin Curt, Martin Schubert (University Clinic Balgrist,

Zürich); Margret Hund-Georgiadis, Kerstin Hug (REHAB Basel, Basel); Hans Georg Koch,

(Swiss Paraplegic Association, Nottwil); Hardy Landolt (Representative of persons with SCI,

Glarus); Hansjörg Koch (SUVA, Luzern); Mirjam Brach, Gerold Stucki (Swiss Paraplegic

Research, Nottwil); Martin Brinkhof, Christine Thyrian (SwiSCI Study Center at Swiss

Paraplegic Research, Nottwil).

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Figure 1: Illustration of the ICF components and their classification trees; the hierarchical structure is exemplified in further detail with the ICF

category d440 Find hand use

13

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Table 1: ICF categories contained in SwiSCI and the ICF set from where they were derived

ICF-Code Title ICF Gen-

eric SetICF Rehab-ilitation Set

Brief _EPA

90%* _EPA

Pat_EPA Ranking#

HP_EPA Ranking# Brief _LT 90%*

_LT Pat_LT Pat_LTRanking#

Pat_HP Ranking#

b126 Temperament and personality functions 17 12 1 6

b130 Energy and drive functions 1 1 6 1 7b134 Sleep functions 1 1 5b152 Emotional functions 1 1 1 11 1 1 4

b270 Sensory functions related to temperature and other stimuli 19

b280 Sensation of pain 1 1 1 1b415 Blood vessel functions 28 7b420 Blood pressure functionsb430 Haematological sytem functions 27 11b440 Respiration functions 1b445 Respiratory muscle functions 15b455 Exercise tolerance functions 1b525 Defecation functions 1 1b530 Weight maintenance functionsb550 Thermoregulatory functions 16b610 Urinary excretory functionsb620 Urination functions 1 1 6 1b640 Sexual functions 1 1

b670 Sensations associated with genital and reproductive functions 20

b710 Mobility of joint functions 1 14 1b715 Stability of joint functions 18b730 Muscle power functions 1 1 1 1 1

16

b735 Muscle tone functions 1 1 1b740 Muscle endurance functions 1 1b750 Motor reflex functions 1

b755 Involuntary movement reaction functions 13

b760 Control of voluntary movement functions 24

b780 Sensations related to muscles and movement functions 17

b810 Protective functions of the skin 1 15 1b840 Sensation related to the skin 1 13s120 Spinal cord and related structures 1 1 1 1s430 Structure of respiratory system 1 13 1s610 Structure of urinary system 1 8 1s720 Structure of shoulder region 29s810 Structure of areas of skin 22 1d155 Acquiring skillsd230 Carrying out daily routine 1 1 1

d240 Handling stress and other psychological demands 1 9 1 1 9

d360 Using communication devices and techniques

d410 Changing basic body position 1 1 1d415 Maintaining a body position 1d420 Transferring oneself 1 1 1d435 Moving objects with lower extremities 1d445 Hand and arm use 1 1 1 16d450 Walking 1 1 1d455 Moving around 1 1 1 1 1d460 Moving around in different locations 1

17

d465 Moving around using equipment 1 4 3 1d470 Using transportation 1 1d475 Drivingd510 Washing oneself 1 1d520 Caring for body parts 1 1d530 Toileting 1 1 7 1d540 Dressing 1 1d550 Eating 1 1 1d560 Drinking 1d570 Looking after one's health 1 1 1 3d620 Acquisition of goods and services 1 1d630 Preparing meals 2 2d640 Doing housework 1d660 Assisting others 1 1 11d710 Basic interpersonal interactions 1d770 Intimate relationships 1 3 4 1 8d820 School education 1 18d840 Apprenticeship (work preparation)

d845 Acquiring, keeping and terminating a job

d850 Remunerative employment 1 1d870 Economic self-sufficiency 1 1 2d910 Community lifed920 Recreation and leisure 1d930 Religion and sprituality 18 10

e110 Products or sustances for personal consumption 1 1

e115 Products and technology for personal use in daily living 1 1

e120 Products and technology for personal 1 1 9 20 1

18

indoor and outdoor mobility and transportation

e125 Products and technology for communication 26

e135 Products and technology for employment 1 25 14

e140 Products and technology for culture, recreation and sport 23 1 15

e150Design, construction and building products and technology of buildings for public use 1

19 1 1 12

e155Design, construction and building products and technology of buildings for private use 1

1

e165 Assets 21e225 Climate 1e310 Immediate family 1 1 1 1e320 Friends 1

e325 Acquaintances, peers colleagues, neighbours and community members 10 1 17

e340 Personal care providers and personal assistants 1 8 1

e355 Health professionals 1 1 1e360 Health-related professionals 30

e415 Individual attitudes of extended family members 1 14

e420 Individual attitudes of friends

e440 Individual attitudes of personal care providers and personal assistants 1 19

e450 Individual attitudes of health professionals 1 1 1 20

e455 Individual attitudes of health-related professionals

19

e460 Societal attitudes

e510 Services, systems and policies for the production of consumer goods

e515 Architecture and construction services, sytems and policies

e525 Housing services, systems and policiese530 Utilities services, systems and policies

e540 Transportation services, systems and policies 1 21

e555 Associations and organizational services, systems and policies 5 5

e575 General social support services, systems and policies 12

e580 Health services, systems and policies 1 1

e585 Education and training services, systems and policies 1 10

Brief = Brief ICF Core Set; EPA = Early Post Acute; Pat = Patients; HP = Health Professionals; LT = Long Term*90% refers to ICF categories which have revealed for the descrition of functioning of persons with SCI as more than 90% of people in the empirical study indicated problems in this ICF category. These ICF categories were, however, not included in the Regression model for developing the statistical set due to their lack of variance.# Ranking refers to the explanatory value of the ICF category; it was ranked according to the size of the regression coefficients which resulted from the Lasso regression analysis in the development of the statistical sets; the smaller the number, the higher the rank.

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Table 2: Table 2: ICF Category Specification and the pool of candidate measurement instruments found in the literature exemplified for b152

Emotional functions and b280 Sensation of pain

ICF category Specification Measurement instrument Type of measurement

Number of items/ questions*

b152 Emotional functions

AnxietyDepression

Hospital Anxiety and Depression Scale SR, OBS 14Centre for Epidemiological Studies Depression Scale SR, SSI 20Patient Health Questionnaire-9 SR, SSI 9Zung Self-Rating Depression Scale SR, SSI 20Montgomery-Asberg Depression Rating Scale OBS 10Hamilton Rating Scale for Depression SSI 21State-Trait Anxiety Inventory SR 40Beck Depression Inventory SR 21Goldberg General Health Questionnaire (Self-completion) SR 28Geriatric Depression Scale SR 15Geriatric Mental State SSI 30Mental Status Questionnaire SSI 10Mental Health Scale of the SF-36 SR 5

b280 Sensation of pain

Shoulder painPain (general)

The International Spinal Cord Injury Pain Basic Data Set OBS, SSI 16The International Spinal Cord Injury Pain Basic Data Set (self-reported version) SR 8Wheelchair User's Shoulder Pain Index SR 15McGill Pain Questionnaire SR 20McGill Pain Questionnaire - Short Form SR 15Classification System for Chronic Pain in SCI OBS, SR 36Donovan SCI Pain Classification System SSI 30The Multidimensional Pain Inventory - SCI version SR 50Quantitative Sensory Testing CT naTunk Classification Scheme SSI variousBrief Pain Inventory SR 17

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SCI Secondary Condition Scale SR 16Numeric Rating Scale SR naVisual Analog Scale SR na

SR = Self-report instrument; OBS = Observational instrument; SSI = Semi-structured interview; CT = Clinical test*Note: Some instruments are available with different length and thus number of items; the number of items of the most widely used versions are listed here.

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Table 3: Linking of instrument exemplified with the Spinal Cord Injury Secondary Comorbidity Scale (SCI-SCS); the far right column identifies

whether the ICF category to which an item has been linked is specified in one of the relevant ICF (Core) Sets considered in SwiSCI

Verbatim health information (e.g. wording of item or instruction)

Response options

What is this piece of information about?

Perspective adopted in

information

Operationali-zation of the perspective

ICF Category

Health problem: decubitus

0=No problem

1=Mild/in-frequent problem

2=Moderate/ occasional problem

3=Significant/ chronic problem

decubitus Descriptive

Integrated Intensity and Frequency

b810 Protective functions of the skinHealth problem: urinary tract infection urinary tract infection Descriptive b620 Urination functionsHealth problem: sexual dysfunction sexual dysfunctions Descriptive b640 Sexual functionsHealth problem: spasticity spasticity Descriptive b735 Muscle tone functionsHealth problem: chronic pain chronic pain Descriptive b280 Sensation of painHealth problem: respiration respiration problems Descriptive b440 Respiration functionsHealth problem: sleep sleep problems Descriptive b134 Sleep functionsHealth problem: injury caused by loss of sensation self-injury Descriptive

nc_health condition; b270 Sensory functions related to temperature and other stimuli

Health problem: contractures contractures Descriptive b710 Mobility of joint functionsHealth problem: heterotopic bone ossification

heterotopic ossification Descriptive nc_health condition; s799 Structures related to movement, unspecified

Health problem: bladder dysfunction bladder dysfunction Descriptive b620 Urination functionsHealth problem: bowel dysfunction bowel dysfunction Descriptive b525 Defecation functionsHealth problem: autonomic dysreflexia autonomic dysreflexia Descriptive b410-b429 Functions of the cardivascular systemHealth problem: postural hypotension postural hypotension Descriptive b410 Heart functionsHealth problem: circulatory problems circulatory problems Descriptive b415 Blood vessel functionsHealth problem: diabetes mellitus diabetes mellitus Descriptive nc_health conditionEPA = Brief SCI ICF Core Set for the early post-acute context; LT = Brief SCI ICF Core Set for the long-term context; nc = not covered

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