Nation-wide survey of the treatment trend of microscopic polyangiitis and granulomatosis with polyangiitis in Japan using the Japanese Ministry of Health, Labour and Welfare Database

In Japan, clinical records of patients with intractable diseases, including microscopic polyangiitis (MPA) and granulomatosis with polyangiitis (GPA), are compiled into a database. This study aimed to understand the current treatment status and changes in treatment regimens from our previous survey. Using data from 2012 and 2013, patients with new-onset MPA and GPA were extracted and analysed. We analysed 1278 MPA and 215 GPA patients. The average age was 71.7 and 62.7 years, respectively. Methylprednisolone pulse therapy was used in 51.2% of MPA patients and 40.5% of GPA patients; the initial prednisolone-equivalent glucocorticoid dose was 39.5 mg/day in MPA and 46.6 mg/day in GPA. Concomitant intravenous or oral cyclophosphamide (CY) was administered to 22.6% of MPA and 56.3% of GPA. Young age, bloody sputum, low serum creatinine, and high C-reactive protein levels were independently associated with CY use in MPA. Compliance with treatment protocol for Japanese patients with myeloperoxidase (MPO)-anti-neutrophilic cytoplasmic antibody-associated vasculitis study criteria or the 2011 clinical practice guidelines for rapidly progressive glomerulonephritis was 42.7% and 49.7%, respectively. MPA was more prevalent than GPA in the registry. Compared to patients with GPA, MPA patients were older and used CY less frequently. No apparent changes in treatment trends were observed from the previous survey.