Determinants of patient and physician global assessments of disease activity in anti-neutrophil cytoplasmic antibody-associated vasculitis

OBJECTIVE: To compare physician and patient assessments of global disease activity in anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV) and to identify associated factors. METHODS: Global disease activity scores (0–10 points) were retrospectively analyzed from physicians and patients with AAV at each outpatient visit from 2010 to 2020. We compared the scores and performed a linear regression with a random effects to identify associated factors. RESULTS: Patients (n = 143, 1,291 pairs, 52% female) had a mean 64 (±15) years of age and a mean disease duration of 9 (±7) years. Patients and physicians global disease activity assessments showed a moderate correlation (Pearson R 0.31, CI [0.23–0.52], p < 0.001). Linear regression showed a strong association between the physician-documented disease activity scores and serum CRP levels (β = 0.22, CI [0.18, 0.28]), disease duration (β = −0.022, CI [−0.04,-0.01]) and patients’ assessment of disease activity (β = 0.08, CI [0.04, 0.12]). By contrast, patient assessments were strongly associated with the degree of pain (β = 0.30, CI [0.25, 0.35]), functional limitations in daily living (HAQ, β = 0.49, CI [0.21, 0.78]) and the global physical well-being (NRS, β = 0.39, CI [0.32, 0.46]). CONCLUSION: Patients’ and physicians’ assessments of disease activity correlated. High CRP levels and disease duration were associated with physician-assessed disease activity scores, while subjective limitations were associated with higher patient-assessed disease activity scores. These findings highlight and support the need to develop and evaluate patient-reported outcomes to assess disease activity in patients diagnosed with AAV.