A nationwide survey on the epidemiology and clinical features of eosinophilic granulomatosis with polyangiitis (Churg-Strauss) in Japan

Objective. We conducted a cross-sectional nationwide survey to determine eosinophilic granulomatosis with polyangiitis (Churg-Strauss) (EGPA) prevalence and clinical features in Japan. Methods. Data for EGPA patients in 2008 were collected from 1,564 hospitals. In total, 965 patients were reported from 365 departments. In a second survey, clinical data for 473 patients were obtained. Results. We estimated that 1,866 (95% CI: 1,640-2,092) patients have EGPA in Japan (prevalence, 17.8/1,000,000). Of the 473 patients in the second survey, 315 fulfilled American College of Rheumatology (ACR) criteria or Lanham's criteria for EGPA. The mean age (+/- SD) of the 315 at onset was 55 +/- 14 years, male to female ratio 1:2. 93% of patients had neurological manifestations, which were the organ system most frequently involved. Among 277 patients tested for myeloperoxidase (MPO)-/p anti-neutrophil cytoplasmic antibody (ANCA), 139 (50%) were positive, while only 6 of 238 were positive for proteinase3 (PR3)-/cANCA. MPO-ANCA-positive patients had renal involvement, mucous membrane or ophthalmological symptoms, and ENT symptoms more frequently, whereas cutaneous lesions and cardiovascular involvement were less common. Conclusion. The prevalence of EGPA and the frequency of MPO-/p-ANCA-positivity in Japanese EGPA patients were mostly similar to those of Western countries. However, female predominance and a high frequency of neurological manifestations characterized Japanese patients.