Prediction potential of serum sulfatide levels at diagnosis for end-stage kidney disease progression in ANCA-associated vasculitis

Abstract

The aim was to investigate the ability of serum sulfatide levels at diagnosis to reflect the cross-sectional activity and further longitudinally predict the occurrence of end-stage kidney disease (ESKD) during the follow-up period in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV), regardless of kidney involvement at diagnosis. This study included 67 patients first diagnosed with AAV with available clinical data, including Birmingham Vasculitis Activity Score (BVAS), erythrocyte sedimentation rate, C-reactive protein, and blood samples at diagnosis. Serum sulfatide levels were assessed using stored serum samples at the time of diagnosis. The median age of the 67 patients (40.3% men and 59.7% women) was 61.0 years. During follow-up, 10 (14.9%) patients progressed to ESKD, and 4 (6.0%) died. Serum sulfatide levels significantly correlated with Five-Factor Score (r = -0.242), erythrocyte sedimentation rate (r = -0.315), and renal manifestation of the BVAS items (r = -0.296), but not BVAS at diagnosis. The cutoff of serum sulfatide levels at diagnosis for ESKD progression was 332.5 pg/mL. However, no significant cutoff of serum sulfatide levels for all-cause mortality was obtained. Patients with serum sulfatide levels ≤ 332.5 pg/mL at diagnosis exhibited both significantly higher frequency of ESKD progression (22.7% vs 0%, P = .012) and lower ESKD-free survival rate than those without (P = .011). This study highlighted the clinical usefulness of measuring serum sulfatide levels at the time of diagnosis as a biomarker to predict ESKD progression in patients with AAV regardless of kidney involvement at diagnosis.