Usefulness of DKK1 in Estimating Vasculitis Activity and End-Stage Kidney Disease in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis Patients

Abstract

Purpose: To investigate whether serum levels of Dickkopf-related protein-1 (DKK1) are clinically useful in estimating cross-sectional vasculitis activity and predicting future prognosis in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Materials and Methods: This study included 76 patients with AAV. Their clinical data were retrospectively reviewed and serum DKK1 levels were measured in blood samples collected and stored at diagnosis. At diagnosis, the Birmingham vasculitis activity score (BVAS) and the five-factor score (FFS) were assessed as AAV activity indices, and the erythrocyte sedimentation rate and Creactive protein (CRP) level were recorded as acute-phase reactants. All-cause mortality and end-stage kidney disease (ESKD) were investigated as poor outcomes during follow-up. Results: Among the 76 patients with AAV (31 males, and 45 females), the median age was 63.5 years. At diagnosis, serum DKK1 levels were significantly correlated with BVAS, FFS, CRP, serum albumin, and serum creatinine levels. Using receiver operating characteristic curve analysis, the cut-off serum DKK1 level for predicting ESKD was determined to be 3925.0 pg/mL. Patients with serum DKK1 levels >= 3925.0 pg/mL at diagnosis displayed a significantly higher risk of ESKD progression (relative risk 5.357) and exhibited a significantly lower cumulative ESKD-free survival rate during follow-up than those with lower levels. Conclusion: The present study is the first to demonstrate that serum DKK1 levels at diagnosis are useful in assessing vasculitis activity at diagnosis and predicting future ESKD progression in patients with AAV.