Clinical implications of peripheral eosinophil count at diagnosis in patients newly diagnosed with microscopic polyangiitis and granulomatosis with polyangiitis

• Published in: Arthritis research & therapy Vol. 25; no. 1; p. 245
• Main Authors: Ha, Jang Woo, Ahn, Sung Soo, Song, Jason Jungsik, Park, Yong-Beom, Lee, Sang-Won
• Format: Journal Article
• Language: English
• Published: England BioMed Central Ltd 15-12-2023; BioMed Central; BMC
• Subjects: Activity; Acute coronary syndromes; Arthritis; Blood cell count; Classification; Correlation analysis; Diagnosis; Drugs; Eosinophil; Eosinophils; Granulomatosis with polyangiitis; Health aspects; Hospitals; Immunosuppressive agents; Inflammatory diseases; Measurement; Medical diagnosis; Microscopic polyangiitis; Mortality; Pathogenesis; Patients; Prognosis; Rheumatology; Signal transduction; Survival analysis; Vein & artery diseases; Wegener's granulomatosis; South Korea; Granulomatosis with polyangiitis; Activity; Microscopic polyangiitis; Mortality; Eosinophil
• ISSN: 1478-6362; 1478-6354; 1478-6362
• DOI: 10.1186/s13075-023-03233-1

This study investigated the clinical implications of peripheral eosinophil count at diagnosis in estimating cross-sectional antineutrophil cytoplasmic antibody-associated vasculitis (AAV) activity and predicting all-cause mortality during follow-up in patients newly diagnosed with microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA).
This study included 224 immunosuppressive drug-naïve patients with peripheral eosinophil count at diagnosis < 1,000/mm
. The Birmingham Vasculitis Activity Score (BVAS), the Five-Factor Score (FFS), erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) at diagnosis were assessed.
The median age of the 224 patients (152 MPA and 72 GPA) was 62.0 years; 35.3% of them were men. At diagnosis, peripheral eosinophil count was significantly correlated with BVAS (P = 0.001), FFS (P = 0.046), ESR (P < 0.001), and CRP (P < 0.001). Deceased patients had a significantly higher median peripheral eosinophil count at diagnosis than surviving patients (310.0/mm
vs. 170.0/mm
, P = 0.004). In addition, patients with MPA and those with cardiovascular and renal manifestations at diagnosis exhibited significantly higher peripheral eosinophil counts than those without. When the optimal cut-off of peripheral eosinophil count at diagnosis for all-cause mortality during follow-up was set at 175.0/mm
, Patients with peripheral eosinophil count at diagnosis ≥ 175.0/mm
exhibited a significantly lower cumulative patients' survival rate than those with peripheral eosinophil count at diagnosis < 175.0/mm
(P = 0.008).
This study was the first to demonstrate that peripheral eosinophil count at diagnosis could estimate cross-sectional AAV activity at diagnosis and contribute to predicting all-cause mortality during follow-up in MPA and GPA patients.