Association between renal-limited vasculitis and relapse of antineutrophil cytoplasmic antibody-associated vasculitis: A single-center retrospective cohort study in Japan

BACKGROUND: Several previous studies have evaluated the predictors of relapse in antineutrophil cytoplasmic antibody-associated vasculitis. Nonetheless, the association between renal-limited vasculitis and relapse has not been evaluated. OBJECTIVE: To assess the association between renal-limited vasculitis and the incidence of relapse in Japan among patients with microscopic polyangiitis/renal-limited vasculitis. METHODS: This retrospective cohort study included consecutive patients in remission at 6 months, with renal-limited vasculitis (n = 24, renal-limited vasculitis group) and microscopic polyangiitis with renal and extra-renal involvement (n = 56, non-renal-limited vasculitis group) between 2004 and 2020. RESULTS: During the median follow-up period of 35 (range, 15‒57) months, 28 (35.0%) patients had a relapse. Multivariable Cox proportional hazards models revealed that the lower estimated glomerular filtration rate (per -10 mL/min/1.73 m(2); adjusted hazard ratio = 0.87, 95% confidence interval: 0.76–0.99; P = 0.043), renal-limited vasculitis (adjusted hazard ratio = 0.23, 95% confidence interval: 0.08–0.68; P = 0.008), and glucocorticoid combined with intravenous cyclophosphamide or rituximab (adjusted HR = 0.32, 95% CI: 0.11–0.96; P = 0.042) were associated with a decreased risk of relapse. Glucocorticoid dose during the observation period was lower in the renal-limited vasculitis group than in the non-renal-limited vasculitis group. CONCLUSIONS: Renal-limited vasculitis was associated with a lower risk of relapse than non-renal-limited vasculitis. Our data may contribute to the development of optimal management for renal-limited vasculitis, which may assist in minimizing the adverse effects of immunosuppressive therapy.