Variation in the Treatment of Children Hospitalized With Antineutrophil Cytoplasmic Antibody-Associated Vasculitis in the US.

OBJECTIVE: There are few reports on the treatment of antineutrophil cytoplasmic antibody-associated vasculitis (AAV) in children. This study characterizes the use of cyclophosphamide, rituximab, and plasma exchange in children hospitalized with AAV in the US.
METHODS: We conducted a retrospective cohort study of children hospitalized with AAV from 2004-2014 utilizing an administrative and billing database from 47 tertiary care pediatric hospitals. All patients had an International Classification of Diseases, Ninth Revision, Clinical Modification discharge code of 446.4 and ≥1 charge for glucocorticoids. Treatment receipt was determined using billing data. Mixed-effects logistic regression was used to evaluate factors associated with the likelihood of receipt of each of the 3 treatments.
RESULTS: During the 11-year study period there were 1,290 admissions for 393 children. The median age at index admission was 14.6 years, and 61% were female. Dialysis or mechanical ventilation was required by 16% and 17% of the children, respectively. The median length of stay was 9 days. The percentages of children receiving cyclophosphamide, rituximab, or both were 57%, 21%, and 10%, respectively, and 22% received plasma exchange. Mechanical ventilation was associated with the receipt of cyclophosphamide and plasma exchange, but not rituximab. There was an increasing trend in the use of rituximab over time during the study period (P < 0.05), and a decreasing trend in the use of cyclophosphamide (P < 0.05). Treatment use varied significantly between hospitals, especially for plasma exchange.
CONCLUSION: The treatment of children with severe AAV is shifting from cyclophosphamide to rituximab, and their need for dialysis, mechanical ventilation, and prolonged hospitalization remains common. Use of plasma exchange is highly variable.