Health-related quality of life in ANCA-associated vasculitis and item generation for a disease-specific patient-reported outcome measure

OBJECTIVE: The antineutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAVs) are multisystem diseases of the small blood vessels. Patients experience irreversible damage and psychological effects from AAV and its treatment. An international collaboration was created to investigate the impact of AAV on health-related quality of life (HRQoL), and develop a disease-specific patient-reported outcome measure to assess outcomes of importance to patients. METHODS: Patients with AAV from the UK, USA, and Canada were interviewed to identify salient aspects of HRQoL affected by AAV. The study was overseen by a steering committee including four patient research partners. Purposive sampling of interviewees ensured representation of a range of disease manifestations and demographics. Inductive analysis was used to identify themes of importance to patients; these were further confirmed by a free-listing exercise in the US. Individual themes were recast into candidate items, which were scrutinized by patients, piloted through cognitive interviews and received a linguistic and translatability evaluation. RESULTS: Fifty interviews, conducted to saturation, with patients from the UK, USA, and Canada, identified 55 individual themes of interest within seven broad domains: general health perceptions, impact on function, psychological perceptions, social perceptions, social contact, social role, and symptoms. Individual themes were constructed into >100 candidate questionnaire items, which were then reduced and refined to 35 candidate items. CONCLUSION: This is the largest international qualitative analysis of HRQoL in AAV to date, and the results have underpinned the development of 35 candidate items for a disease-specific, patient-reported outcome questionnaire.