(024) Mortality in an Eosinophilic Granulomatosis with Polyangiitis (EGPA) Incident Cohort: A Retrospective Study in England

Background: EGPA is a rare disorder characterized by eosinophilic inflammation and systemic vasculitis. Despite advancements in understanding its clinical manifestations, there is a critical knowledge gap regarding mortality outcomes in incident EGPA cases.

Objectives: To describe mortality rates in an incident cohort of individuals with EGPA in England versus the general population.

Methods: The analysis used Clinical Practice Research Datalink (CPRD Aurum) data from January 1, 2006 to February 28, 2020, linked with Hospital Episode Statistics (HES) and national death registry. The study population included first-time EGPA diagnoses (2006–2019) with ≥1 year prior history in England. Follow-up extended from diagnosis until death, deregistration, last GP data collection, or study end. We assessed EGPA incidence, primary causes of death, and calculated standardized mortality ratios (SMRs) using national rates. Deaths were stratified by index year, and Five Factor Score (FFS) 1996 and 2009 (prognosis tools at diagnosis). Kaplan-Meier 5-year survival rates were calculated, and Cox proportional hazards models estimated hazard ratios (HR, 95% CIs).

Results: 486 individuals with incident EGPA were identified, giving an annual incidence rate of 3.04 [95% CI 2.77; 3.32] cases per million person-years. No significant sex or temporal differences were observed. Mean age at diagnosis was 57.9 (15.2) years, with 92.6% aged ≥35. Mean follow-up was 5.4 (3.7) years, with 98 (20.2%) deaths. EGPA was the primary cause in 11.2% of deaths. Patients had a 2.3-fold higher mortality rate than the age-adjusted national population (SMR: 2.3 [95% CI: 1.9; 2.8]). Circulatory/cardiovascular diseases accounted for 29.6% of deaths, presenting a 2.6-fold increase. The 5-year survival rate was 82.3% (95% CI 78.1; 85.7). Mortality rates per 1,000 person-years by index year were 39 [95% CI: 29.0; 51.3] for 2006-2010, 32 [95% CI: 22.1; 44.6] for 2011-2015, and 48.5 [95% CI: 25.8; 83.0] for 2016-2019. Mortality rates were higher with increasing FFS 1996 scores: 239 [95% CI: 114.6; 439.5] for patients with FFS=2, 61.2 [95% CI: 40.3; 89.0] with FFS=1, and 28.3 [95% CI: 21.6; 36.3] with FFS= 0. The FFS 2009 version showed a similar increasing trend.

Conclusions: In incident EGPA, the 5-year survival rate, with a mortality ratio two-fold higher than that of the general population, signals a need for improved care. Diagnosis year showed no impact on mortality, but higher FFS scores were linked to increased mortality, consistent with previous literature.