Osteoarthritis is among the 3 most disabling conditions having a remarkable public health impact in developed countries. It also has a high prevalence in the increasing population of elderly people. Research and clinical management of patients with osteoarthritis relies on the sound measurement of pain and functional limitations. The Outcome Measures in Rheumatology Clinical Trials group (OMERACT) and the 5th WHO/ILAR Task Force (World Health Organization/International League Against Rheumatism) recommended the use of condition-specific health-status measures to assess the domains pain, physical function, joint imaging, and patient global assessment in clinical research and practice. In contrast to the OMERACT perspective, which focuses on functioning and health as an outcome of the disease process to be evaluated in phase-III trials, functioning and health is not merely an outcome, but the starting point for assessing functioning and health of patients. With the ICF it is now possible to define the typical spectrum of problems in functioning of patients with osteoarthritis under consideration of environmental factors in a more systematic way using a globally agreed-upon language.

To do this, the ICF Research Branch and the WHO with the scientific support of Rehabilitationskrankenhaus/ Ulm University (Germany), Ludwig-Maximilian University (Germany), Swiss Association of Physical Therapy (Switzerland), University of Vienna (Austria), Hannover Medical School (Germany), Bone and Joint Decade, the European League against Rheumatism (EULAR) and the EU Health Monitor Project Group, initiated a project to develop internationally-accepted and evidence-based ICF Core Sets for osteoarthritis. This project was part of a larger project examining 12 chronic conditions with a high burden of disease.

The preparatory phase included a systematic literature review, a Delphi exercise and an empirical data collection using the ICF checklist:

• The systematic literature review was performed to identify and compare the concepts contained in outcome measures of randomized, controlled clinical trials published from 1991-2000 involving patients with osteoarthritis.
• The international expert survey (via email) using the Delphi technique was conducted with 29 health professionals, experts on the treatment of persons with osteoarthritis, to identify the set of domains that best describe the prototypical spectrum of problems in functioning and health in persons with osteoarthritis from the of health professional perspective.
• The multicentre cross-sectional study using the ICF checklist with a convenient sample of 53 patients undergoing inpatient or outpatient rehabilitation was performed to identify the common problems experienced by persons with osteoarthritis.

An international ICF consensus conference took place from 26-29 April 2002 at a quiet monastery situated in a pleasant landscape far from any city and distractions. The aim of the conference was to establish the Comprehensive and Brief ICF Core Sets for patients with osteoarthritis. Seventeen experts from 7 different countries decided which ICF categories are to be included in the ICF Core Sets for osteoarthritis following a formal, decision-making and consensus process which integrated the results from the 3 preparatory studies.

55 ICF categories were selected for inclusion in the Comprehensive ICF Core for osteoarthritis. These categories can be taken into account when conducting a comprehensive, multidisciplinary assessment. Out of the 55 Comprehensive ICF Core Set categories, 13 ICF categories were selected as categories for the Brief ICF Core for osteoarthritis. The Brief ICF Core Set can be used in assessing patients participating in a clinical study on osteoarthritis.

Validation studies have been conducted.

For more information, feel free to contact the ICF Research Branch (melissa.selb@paranet.ch).

• Comprehensive & Brief ICF Core Sets for osteoarthritis (download PDF)