Background: So far, there has been no tool to estimate activity at diagnosis and predict all-cause mortality in patients with ANCA-associated vasculitis (AAV). Hence, we determined the initial predictors of them in patients with AAV.
Methods:We retrospectively reviewed the medical records of 182 patients with AAV. Severe AAV was defined as Birmingham Vasculitis Activity Score (BVAS) ≥ 16.The cutoffs were extrapolated by the receiver operator characteristic (ROC) curve.The odds ratio (OR) and the relative risk (RR) were assessed using the multivariable logistic regression analysis and the chi-square test, respectively.
Results:In the comparison analysis, patients with severe AAV exhibited the higher neutrophil and platelet counts, creatinine, erythrocyte sedimentation rate and C-reactive protein, and the lower lymphocyte count, hemoglobin, and serum albumin than those without. In the multivariable logistic regression analysis, creatinine ≥ 0.9 mg/dL (OR 2.264), lymphocyte count ≤ 1430.0/mm 3 (OR 1.856), and hemoglobin ≤ 10.8 g/ dL (OR 2.085) were associated with severe AAV. We developed a new equation of a multivariable index for AAV (MVIA) = 0.6 × (Lymphocyte count ≤ 1430.0/mm 3 ) + 0. 7 × (Hemoglobin ≤ 10.8 g/dL) + 0.8 × (Creatinine ≥ 0.9 mg/dL). The optimal cutoff of MVIA for severe AAV was set as 1.35. Severe AAV was identified more frequently in patients with MVIA at diagnosis ≥1.35 than those without (RR 4.432). Patients with MVIA at diagnosis ≥1.35 exhibited the lower cumulative patient survival rate than those without.
Conclusion:Multivariable index for AAV could assess the cross-sectional activity and predict all-cause mortality in patients with AAV.