Could hypereosinophilia at diagnosis estimate the current activity or predict relapse in systemic immunosuppressive drug-naïve patients with eosinophilic granulomatosis with polyangiitis?

In this study, we investigated whether hypereosinophilia (peripheral eosinophil ≥ 1500/mm³) at diagnosis could estimate the increased current activity and predict the poor prognosis during follow-up in patients with eosinophilic granulomatosis with polyangiitis (EGPA). We retrospectively reviewed the medical records of 42 patients with EGPA and finally included 30 systemic immunosuppressive drug-naïve patients. We obtained clinical and laboratory data including clinical manifestations, Birmingham vasculitis activity score (BVAS), five-factor score (FFS) (2009), and routine laboratory results. Hypereosinophilia was defined as peripheral eosinophil ≥ 1500/mm³. We divided EGPA patients based on hypereosinophilia and compared variables between the two groups. The cumulative relapse-free survival rates were compared by the Kaplan–Meier survival analysis. Patients with hypereosinophilia more commonly exhibited cutaneous manifestation than those without (50.0% vs. 14.3%, P = 0.038), but there were no significant differences in BVAS and FFS (2009) at diagnosis. Patients with hypereosinophilia showed the higher median WBC (14,200.0/mm³ vs. 7940.0/mm³) and CRP (17.6 mg/L vs. 2.0 mg/L) at diagnosis than those without. During follow-up, patients with hypereosinophilia at diagnosis exhibited the similar cumulative relapse-free survival rate to those without (P = 0.393). Whereas, patients with FFS (2009) at diagnosis ≥ 2, which was a well-known predictor of the poor prognosis of EGPA, exhibited the lower cumulative relapse-free survival rate than those with FFS (2009) < 2 (P = 0.030). Hypereosinophilia at diagnosis could neither estimate the current activity nor predict relapse in systemic immunosuppressive drug-naïve patients with EGPA unlike theoretical assumption.