Comparison of Outcomes Between Japanese Patients With Older‐Onset Granulomatosis With Polyangiitis/Microscopic Polyangiitis and Younger‐Onset Patients in Daily Clinical Practice: A Two‐Center Retrospective Study in Japan

ABSTRACT Aims Although previous studies have reported poor outcomes in older‐onset (≥ 75 years old) antineutrophil cytoplasmic antibody (ANCA)‐associated vasculitis (AAV) compared with younger‐onset AAV, the distinct cause of poor prognosis remains unclear. This study aimed to investigate the clinical features, therapies, and outcomes of older patients with granulomatosis with polyangiitis (GPA) and patients with microscopic polyangiitis (MPA) compared to younger‐onset patients. Methods This two‐center retrospective cohort study enrolled 70 newly‐onset Japanese patients with AAV (GPA and MPA) from the Fukushima Medical University Hospital and Ohta‐Nishinouchi Hospital in Fukushima, Japan, between 2004 and 2019. Clinical records were retrospectively reviewed, and clinical features and outcomes (1‐year and 3‐year survival by the Kaplan–Meier method) were compared between older and younger GPA/MPA groups, respectively. Results Clinical features of the older GPA/MPA group were similar to those of the younger GPA/MPA group; however, the older GPA group showed severe inflammation and the older MPA group had an increased frequency of renal involvement and fever. The 1‐year survival in the older MPA group was significantly lower than that in the younger MPA group. Immunosuppressive therapy including cyclophosphamide, rituximab, and other immunosuppressive agents was important to sustain the survival of patients with GPA/MPA. Conclusions Older patients with GPA/MPA may have specific clinical features; careful observation is needed during the treatment of older patients with MPA. Immunosuppressive therapy may improve the prognosis of patients with AAV.