IVIG Compared With IVIG Plus Infliximab in Multisystem Inflammatory Syndrome in Children

OBJECTIVES: To compare initial treatment with intravenous immunoglobulin (IVIG) versus IVIG plus infliximab in multisystem inflammatory syndrome in children (MIS-C). METHODS: Single-center retrospective cohort study of patients with MIS-C who met Centers for Disease Control and Prevention criteria and received treatment from April 2020 to February 2021. Patients were included and compared on the basis of initial therapy of either IVIG alone or IVIG plus infliximab. The primary outcome was need for additional therapy 24 hours or more after treatment initiation. RESULTS: Seventy-two children with MIS-C met inclusion criteria. Additional therapy was needed in 13 of 20 (65%) who received IVIG alone and 16 of 52 (31%) who received IVIG plus infliximab (P = .01). The median (interquartile range) ICU lengths of stay were 3.3 (2.2 to 3.8) and 1.8 (1.1 to 2.1) days, respectively (P = .001). New or worsened left ventricular dysfunction developed in 4 of 20 (20%) and 2 of 52 (4%) (P = .05), and new vasoactive medication requirement developed in 3 of 20 (15%) and 2 of 52 (4%), respectively (P = .13). The median percentage changes in the C-reactive protein level at 24 hours posttreatment compared with pretreatment were 0% (-29% to 66%) and -46% (-62% to -15%) (P < .001); and at 48 hours posttreatment, -5% (-41% to 57%) and -70% (-79% to -49%) respectively (P < .001). There was no significant difference in hospital length of stay, time to fever resolution, vasoactive medication duration, or need for diuretics. CONCLUSIONS: Patients with MIS-C initially treated with IVIG plus infliximab compared with those treated with IVIG alone were less likely to require additional therapy and had decreased ICU length of stay, decreased development of left ventricular dysfunction, and more rapid decline in C-reactive protein levels.