Evaluating disease burden in German AAV patients using the AAV-PRO: associations with disease activity, physical...

The disease-specific patient-reported outcome for ANCA-associated vasculitis (AAV-PRO) was developed by the Outcome Measures in Rheumatology (OMERACT) group. Its interpretation in routine clinical practice remains challenging due to limited evidence regarding the association with established clinical outcome measures.

We conducted a prospective cohort study of 70 AAV-patients who completed the AAV-PRO and the following additional questionnaires: Short Form-36 (SF-36), assessing health-related quality of life; Fatigue Severity Scale (FSS) measuring fatigue severity; Index zur Messung von Einschränkungen der Teilhabe (IMET), assessing restrictions in participation in everyday life; Funktionsfragebogen-Hannover (FFbH), evaluating abilities and limitations in daily activities; Patient Health Questionnaire-9 (PHQ-9), screening for depressive symptoms; and Life Orientation Test-Revised (LOT-R), assessing optimism and expectations. Physicians assessed disease activity, related damage and glucocorticoid side-effects using the Birmingham Vasculitis Activity Score (BVAS), vasculitis damage index (VDI) and glucocorticoid toxicity index (GTI).

70 patients with AAV participated in the study, including 45 patients with GPA; 64.3%, 16 with EGPA; 22.9%, and 9 with MPA; 12.8%. At study inclusion, the mean disease duration was 10.5 years (SD 7.9). Patients with active disease had higher AAV-PRO scores across all domains. We observed strong correlations between AAV-PRO subdomains and the following validated measures: "Systemic symptoms" with SF-36 physical function (r = -0.72, 95% CI -0.85 to -0.58) and FFbH (r = -0.88, 95% CI -0.56 to -0.97); "Social and emotional impact" with SF-36 social role functioning (r = -0.8, 95% CI -0.87 to -0.69), IMET (r = 0.7, 95% CI 0.55 to 0.81) and FFbH (r = -0.75, 95% CI -0.94 to -0.23); "Concerns about the future" with SF-36 social role functioning (r = -0.71, 95% CI -0.81 to -0.55) and FFbH (r = -0.77, 95% CI -0.94 to -0.27); "Physical function" with SF-36 physical function (r = -0.9, 95% CI -0.94 to -0.84) and IMET (r = 0.79, 95% CI 0.68 to 0.87).

The German AAV-PRO captures patient-perceived disease burden, complementing traditional clinical outcome measures. Its multidimensional approach allows assessment of functional, psychosocial and symptom-related aspects of AAV, supporting its use in clinical practice.