Association of the AAV-PRO questionnaire with established outcome measures in AAV

Abstract

Abstract Objectives The ANCA-associated vasculitis (AAV) patient-reported outcome (AAV-PRO) questionnaire was developed to capture the impact of AAV and its treatment. We investigated the association of specific AAV-PRO domains with disease activity and extent, damage, depression, health-related quality of life, and treatment. Methods In a prospective longitudinal study, AAV-PRO, Beck’s depression inventory (BDI), Short Form 36 (SF-36), BVAS and Vasculitis Damage Index (VDI) were completed at baseline (t1) and after 3–6 months (t2). In addition, patient data (including diagnosis, therapies, relapses, and organ manifestations) were recorded. Data were analysed by t-tests and correlation-based regression analyses. Results A total of 156 patients with AAV participated. The mean BVAS at the time of enrolment was 1.4 ± 3.74. The median AAV-PRO domain scores were higher in patients reporting ‘active disease‘ compared with those reporting ‘in remission’ (P < 0.001). In the correlation analyses, all AAV-PRO domain scores correlated strongly with the BDI (all r ≥ 0.319, all P ≤ 0.001) as well as with all eight SF-36 subdomains (all |r|≥0.267, all P ≤ 0.001). The regression analyses showed that AAV-PRO domains were strongly predicted by the BDI and SF-36 domains (|β| ≥ 0.240 for the strongest predictor of each domain). In the longitudinal comparison (t1/t2), there were no significant changes in the overall results. Conclusion Our data show convergent validity for all AAV-PRO subdomains, using the established questionnaires BDI and SF-36. The AAV-PRO domains scores were not correlated with clinician-derived instruments (including the BVAS and the VDI). Thus, we regard the AAV-PRO questionnaire as a valuable measure of outcomes that might complement traditional end-points in clinical trials.