Validating the International Classification of
Functioning, Disability and Health Comprehensive
Core Set for Rheumatoid Arthritis From the
Patient Perspective: A Qualitative Study
TANJA A. STAMM,1ALARCOS CIEZA,2MICHAELA COENEN,3KLAUS P. MACHOLD,4
VALERIE P. K. NELL,4JOSEF S. SMOLEN,4AND GEROLD STUCKI3
Objective. To validate the International Classification of Functioning, Disability and Health (ICF) Comprehensive Core
Set for Rheumatoid Arthritis (RA) from the patient perspective.
Methods. Patients with RA were interviewed about their problems in daily functioning. Interviews were tape recorded
and transcribed verbatim. Interview texts were divided into meaning units. The concepts contained in these meaning
units were linked to the ICF according to 10 established linking rules. Of the transcribed data, 15% were analyzed and
linked by a second health professional. The degree of agreement was calculated using the kappa statistic.
Results. Twenty-one patients were interviewed. Two hundred twenty different concepts contained in 367 meaning units
were identified in the qualitative analysis of the interviews and linked to 109 second-level ICF categories. Of the 76
second-level categories from the ICF RA Core Set, 63 (83%) were also found in the interviews. Twenty-five second-level
categories, which are not part of the current ICF RA Core Set, were identified in the interviews. The result of the kappa
statistic for agreement was 0.62 (95% bootstrapped confidence interval 0.59–0.66).
Conclusion. The validity of the ICF RA Core Set was supported by the perspective of individual patients. However, some
additional issues raised in this study but not covered in the current ICF RA Core Set need to be investigated.
KEY WORDS. International Classification of Functioning, Disability and Health (ICF); Patient perspective; Comprehensive
ICF Core Set for RA; Rheumatoid arthritis.
Rheumatoid arthritis (RA) is a chronic disabling disease
(1) that often is associated with the inability to conduct
occupations, such as paid work and other daily activities.
Ultimately, patients’ daily activities may become limited
and their societal participation restricted (2–9). People
with RA experience a decrease in overall functional ability
and quality of life (2) and a greater loss of their life activ-
ities than people without RA (7).
Assessing, exploring, and understanding the patients’
daily functioning are essential when treating people with
RA. Health professionals who specialize on rehabilitation
focus on the daily functioning of the patient (10). Current
recommendations regarding assessment of disease and dis-
ease consequences include recommendations to measure
function, mainly referring to physical function (11). To
map and assess daily functioning and disability from a
holistic biopsychosocial perspective in rehabilitation, the
framework of the World Health Organization International
Classification of Functioning, Disability and Health (ICF)
can be used. The overall aim of the ICF classification is to
provide a unified and standard language for the descrip-
tion of health and health-related conditions in rehabilita-
tion and a common framework for all health professions
Supported by the ICF Core Sets Validation Study by the
European League Against Rheumatism with the scientific
advisory group consisting of Annelies Boonen, Alarcos
Cieza, Valerie P. K. Nell, Tanja A. Stamm, Gerold Stucki,
and Till Uhilg.
1Tanja A. Stamm, MSc, MBA, Mag Phil, OTR: Vienna Med-
ical University, Vienna, Austria, German Institute of Medical
ians-University, Munich, Germany;
MPH, Dipl. Psych: German Institute of Medical Documenta-
tion and Information, IMBK, Munich, Germany;
Coenen, MPH, Dipl. Psych, Gerold Stucki, MD, MS: German
Institute of Medical Documentation and Information, IMBK,
4Klaus P. Machold, MD, Valerie P. K. Nell, MD, Josef S.
Smolen, MD: Vienna Medical University, Vienna, Austria.
Address correspondence to Tanja A. Stamm, MSc, MBA,
Mag Phil, OTR, Vienna University, Department of Internal
Medicine III, Division of Rheumatology, Wa ¨hringer Gu ¨rtel
18-20, A – 1090 Vienna, Austria. E-mail: Tanja.Stamm@
Submitted for publication November 12, 2004; accepted in
revised form January 22, 2005.
2Alarcos Cieza, PhD,
Arthritis & Rheumatism (Arthritis Care & Research)
Vol. 53, No. 3, June 15, 2005, pp 431–439
© 2005, American College of Rheumatology
The ICF has 2 parts, each containing separate compo-
nents. Part 1 covers functioning and disability and in-
cludes the components body functions (b) and structures
(s) and activities and participation (d). Part 2 covers con-
textual factors and includes the components environmen-
tal factors (e) and personal factors (Figure 1). Each compo-
nent consists of several chapters and within each chapter,
categories, which are the units of the classification (14).
Chapters represent health domains that are used to orga-
nize the classification. An example is Chapter 5: self-care
within the component activities and participation.
To facilitate the application of the ICF in clinical prac-
tice, specific Comprehensive ICF Core Sets (abbreviated in
this article as ICF Core Sets) for certain health conditions
have been developed. ICF Core Sets are short lists of ICF
categories that are important for patients with a specific
disease. The ICF Core Set for RA is a short list of ICF
categories that are important for patients with RA and is
meant to include all relevant ICF categories by represent-
ing the typical spectrum in functioning of patients with
The ICF RA Core Set was developed by rheumatology
health professionals in a formal decision-making and con-
sensus process. In this process, evidence was integrated
from preliminary studies. These preliminary studies in-
cluded a delphi exercise involving health professionals as
experts, a systematic literature review, and an empiric data
collection that was done quantitatively with a checklist
(15). The consensus process revealed a current, prelimi-
nary version of the ICF RA Core Set. The current, prelim-
inary version of the ICF RA Core Set now needs to be
validated and further developed.
One aspect in this validation process is to explore the
patient perspective. To explore the perspective of patients,
a qualitative research approach was considered most ap-
propriate. When measuring and assessing daily function-
ing in people with RA from a holistic biopsychosocial
perspective in rehabilitation, it is important to include the
patient perspective because personal values for outcomes
vary between and within patients and professionals (16,17).
Qualitative methodology provides the possibility of ex-
ploring the perspective of those who experience the dis-
ease (the patient perspective) (16,18,19).
ICF Core Sets have been developed for other chronic
diseases apart from RA, and preliminary versions have
been established. The next step is validation. The ICF RA
Core Set is the first to undergo validation. Therefore, the
present study is also considered a methodologic pilot
study for the validation and development of ICF Core Sets
for other diseases and health conditions.
The objective of this study therefore was to validate the
current, preliminary version of the ICF RA Core Set from
the patient perspective using a qualitative approach. The
specific aims were to 1) explore the aspects of functioning
and health that are important to patients with RA, 2)
examine how these aspects are represented by the current
version of the ICF RA Core Set, 3) possibly identify aspects
of functioning important for people with RA that are not
included in the ICF RA Core Set, and 4) explore the qual-
itative methodology in this pilot study for further valida-
tion and development of ICF Core Sets for other diseases.
We conducted a qualitative study based on interviews
with patients with RA.
Patients. All patients with RA diagnosed according to
the revised American College of Rheumatology (formerly
the American Rheumatism Association) criteria (20) who
had appointments on 5 consecutive, randomly selected
days in the Rheumatology Outpatient Clinic of the Vienna
Medical University were asked to participate. Patients
who were willing to participate gave written informed
consent according to the Declaration of Helsinki 1996. The
study was approved by the Institutional Review Board of
the Vienna Medical University.
Sample size. A small sample size with a diverse range
of participants was used to obtain the required level of rich
and meaningful data (21). Patients were included in the
study until saturation was reached. Saturation refers to the
point at which an investigator has obtained sufficient in-
formation from the field (22). Saturation was defined in
our study as the point during data gathering when the
linking of the qualitative data of 2 consecutive interviews
revealed no additional information that was not obtained
Interviews. All participants were interviewed by the
same interviewer (TS). The interviews were tape recorded
and transcribed verbatim. A short introduction to the con-
cepts of the ICF was given in lay terms to all patients at the
beginning of each interview. Then, 2 different types of
interviews were performed. Interview type 1 included
Figure 1. The model of the International Classification of Func-
tioning, Disability and Health (ICF). The model shows the rela-
tionship between the ICF components body functions (b) and
structures (s) and activities and participation (d) and the contex-
tual factors environmental factors (e) and personal factors. Each
component consists of chapters that then consist of categories.
Within the component activities and participation, Chapter 5:
self-care includes the categories “d510 washing oneself” (second-
level) and “d5100 washing body parts” (third level) among many
432 Stamm et al
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