Circulating Malondialdehyde Is a Potential Biomarker for Predicting All-Cause Mortality during Follow-Up by Reflecting Comprehensive Inflammation at Diagnosis in Patients with Antineutrophil Cytoplasmic Antibody-Associated Vasculitis.

Background and Objectives: To investigate whether circulating malondialdehyde (cMDA) at diagnosis could contribute to reflecting cross-sectional comprehensive inflammation or vasculitis activity and further predicting all-cause mortality during follow-up in patients with antineutrophil cytoplasmic antibody-associated vasculitis (AAV). Materials and Methods: This study included 78 patients with AAV. Erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) levels were collected as indices reflecting cross-sectional comprehensive inflammation, whereas the Birmingham vasculitis activity score (bVAS), and the five-factor score (FFS) were reviewed as AAV-specific indices. All-cause mortality was considered to be a poor outcome during follow-up. cMDA was measured from stored sera. Results: The median age of the 78 patients (32 men and 46 women) was 63.0 years. The median BVAS, FFS, ESR, and CRP were 5.0, 0, 24.5 mm/h, and 3.4 mg/L, respectively. Six patients died during the median follow-up duration based on all-cause mortality at 26.7 months. At diagnosis, cMDA was significantly correlated with cross-sectional ESR but not with BVAS or FFS. Compared to patients with cMDA < 221.7 ng/mL, those with cMDA ≥ 221.7 ng/mL at diagnosis exhibited an increased relative risk (RR 12.4) for all-cause mortality and further showed a decreased cumulative patient survival rate. Cox analyses revealed that cMDA ≥ 221.7 ng/mL (hazard ratio 24.076, p = 0.007) exhibited an independent association with all-cause mortality during follow-up in patients with AAV. Conclusions: cMDA at diagnosis may be a potential biomarker for predicting all-cause mortality during follow-up by reflecting comprehensive inflammation at diagnosis in patients with AAV.