# Circulating GDF15 May Estimate Vasculitis Activity and Predict Poor Outcomes During the Disease Course of ANCA-Associated Vasculitis

## TL;DR

This study shows that GDF15 levels in the blood can help estimate disease severity and predict poor outcomes in patients with ANCA-associated vasculitis.

## Contribution

The study identifies GDF15 as a potential biomarker for disease activity and outcomes in AAV patients.

## Key findings

- Higher GDF15 levels correlate with higher Birmingham Vasculitis Activity Score (BVAS) at diagnosis.
- Elevated GDF15 levels are linked to increased risk of mortality and progression to end-stage kidney disease.
- Patients with high GDF15 levels show significantly lower survival rates.

## Abstract

Objective: This study investigated whether circulating growth differentiation factor 15 (GDF15) at diagnosis could estimate the Birmingham Vasculitis Activity Score (BVAS) and potentially predict all-cause mortality and end-stage kidney disease (ESKD) during follow-up in patients with antineutrophil cytoplasmic antibody (ANCA)-associated vasculitis (AAV). Methods: This study included 79 patients selected from a cohort of Korean patients with AAV. Circulating GDF15 was measured from patients’ sera collected at diagnosis and stored at −80 °C. Clinical data at diagnosis and during follow-up were reviewed. Results: The median age was 64.0 years (40.5% men, and 59.5% women). Median circulating GDF15 was measured as 995.0 pg/mL. Of the 79 patients, 6 (7.6%) died and 20 (25.3%) progressed to ESKD during the disease course. Circulating GDF15 levels were significantly correlated with BVAS (r = 0.340) at diagnosis. Patients with circulating GDF15 ≥ 3350.5 pg/mL exhibited a significantly higher risk of the highest tertile of BVAS than those without (relative risk [RR], 11.229). Similarly, patients with circulating GDF15 ≥ 2239.5 pg/mL and ≥2208.5 pg/mL showed higher risks of all-cause mortality (RR, 7.733) and progression to ESKD (RR 7.125) than those without. Patients with circulating GDF15 ≥ 2239.5 pg/mL and ≥2208.5 pg/mL also showed significantly lower patient and ESKD-free survival rates than those without. Conclusions: Circulating GDF15 at diagnosis is useful in estimating BVAS and potentially predicts all-cause mortality and ESKD progression in patients with AAV.