Background/Purpose: Eosinophilic granulomatosis with polyangiitis (EGPA, formerly Churg-Strauss) belongs to the group of anti-neutrophil cytoplasmic antibody (ANCA)-associated vasculitides (AAV). There are no recent data on the epidemiology and outcome of EGPA in France.

Methods: Patients with EGPA were identified from 2013 to 2019 for the epidemiological objective and from 2012 to 2016 for the longitudinal analysis in the French National Health System database, which covers 98% of the French population. To be included, patients had to be affiliated to the general health insurance system and either have full coverage for EGPA (ICD-10 code M30 Polyarteritis nodosa and related conditions or M301 Periarteritis with pulmonary involvement [Churg-Strauss]) or have been hospitalised for EGPA (ICD-10 code M301 only). A sensitivity analysis was also performed on a population restricted to patients who had at least 3 courses of oral glucocorticoids in the year after diagnosis.

Results: There were 7,238 subjects in the main analysis and 3,328 subjects in the sensitivity analysis, corresponding to a prevalence of 85.3 cases/million and 38.4 cases/million, respectively. There were 1,650 and 1,035 new cases/year in the main and the sensitivity analysis, corresponding to an incidence of 3.5 and 2.1 cases/million/year, respectively. In the incident case population (main analysis), the mean age was 61.7 ± 17.4 years, with 57.1% of females; the mean duration of follow-up was 60.1 ± 22.3 months.

The mean duration of oral glucocorticoids was 45.6 months and 53.1 months in the main and sensitivity analyses, respectively. The mean monthly dose of glucocorticoids during the first 6 months was 449.5 mg (i.e. 15 mg/d) in the main analysis and 693.9 mg (i.e. 23.1 mg/d) in the sensitivity analysis, while it gradually decreased to reach a plateau from the 3rd year and until the 8th year of follow-up, with a mean monthly dose of glucocorticoids during these years of approximately 135 mg (or 4.5 mg/d) in the main analysis and 190 mg (or 6.3 mg/d) in the sensitivity analysis.

During follow-up, 62.6% of patients in the main analysis and 69.1% of patients in the sensitivity analysis had at least one complication or new comorbidity, the most common being osteoporosis (21.6% and 31.4%, respectively), followed by arterial hypertension (20.7% and 21.7%), arrhythmia (14.6% and 15.2%) and diabetes (10.9% and 12.2%).

The age- and sex-standardized mortality rate of EGPA was 11.3/1000 patients (main analysis) and 9.7/1000 (sensitivity analysis), compared with 9.2/1000 patients in the general population. At 5 years, the rate of hospitalization for asthma exacerbation was 10.2% (8.7-11.8), and the rate of EGPA relapse was 69.3% (66.9-71.6).

Conclusion: The incidence of EGPA estimated in a large population is consistent with previous estimates but prevalence seems to be higher. This comprehensive study of treatments and complications highlights the extensive and prolonged use of oral corticosteroid therapy. Complications are common and include osteoporosis, hypertension, cardiac arrhythmias, and diabetes. Overall survival of EGPA is excellent but relapses are still frequent, suggesting that the burden of disease remains high.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/epidemiology-and-outcome-of-eosinophilic-granulomatosis-with-polyangiitis-in-france/