Background/Purpose:

The International Classification of Functioning, Disability and Health (ICF) is a general health model endorsed by the World Health Organization. It describes health along 4 domains: body functions, body structures, activities and participation, and environmental factors. There is interest in applying ICF to human disease states to determine what domains of health are captured by current disease assessment tools.

In 2010 the OMERACT (Outcome Measures in Rheumatology Clinical Trials) initiative endorsed the Core Set of outcome measures for ANCA-associated vasculitis (AAV). The Core Set includes a choice of 3 disease activity measures (Birmingham Vasculitis Activity Score (BVAS), BVASv.3, BVAS for Wegener’s Granulomatosis), 1 damage measure (Vasculitis Damage Index (VDI)), 1 patient-reported outcome (Short Form-36 (SF36)), and death. This study examined the extent to which the AAV Core Set captures the impact of AAV relevant to patients, using the ICF classification.

Methods:

Outcome measures included in the OMERACT Core Set for AAV were linked to the corresponding ICF categories according to the previously established ICF linkage rules.

Two focus groups involving 9 patients were conducted. Patients identified aspects of disease that have an important impact on their lives. Focus group transcripts were analyzed according to standard qualitative analytic techniques. Identified concepts were linked to ICF categories. Coverage of various ICF domains by the Core Set tools was compared to coverage by the items identified by patients.

Results:

All items of the Core Set’s measures of disease activity and damage linked to categories of the ICF domains ‘body functions’ and ‘body structures’. In contrast, the majority of items of SF36 linked to categories of the ICF domain ‘activities and participation’, with the remaining smaller number of items linking to categories of ‘body functions’ domain.

AAV Core Set instruments and patients focus on different aspects of the domain ‘body functions’. The Core Set covers specific organ functions (e.g. hearing) while patients focus on sensations associated with these functions (e.g. ear fullness); similarly, the Core Set covers pain in specific body parts, while patients identify generalized and multifocal pain as most relevant. Sleep, temperament and personality, and exercise tolerance were areas in the ‘body functions’ domain identified by patients as important but not measured by any of the Core Set tools.

One broad area in the domain ‘activities and participation’ that was identified as crucial by patients but not covered by the Core Set is “interpersonal interactions and relationships”. Similarly, environmental factors are not part of the AAV Core Set, while for patients a number of such factors are relevant in establishing the impact of AAV (various products and technology, support and relationships, attitudes, and services).

Conclusion:

The ICF model is useful for identifying areas of health important for capturing the impact of AAV from patients’ perspective but not covered by the currently utilized AAV outcome tools. These observations support the ongoing initiatives to expand the scope of outcome assessment in AAV, especially to include patient-reported outcomes.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/the-use-of-the-international-classification-of-function-disability-and-health-as-a-conceptual-framework-for-comparison-of-the-content-of-core-outcome-instruments-with-the-patient-perspective-in-vascu/