Variation in Early Anakinra Use and Short-Term Outcomes in Multisystem Inflammatory Syndrome in Children

Area of Science:

• Pediatric rheumatology
• Pediatric critical care
• Immunology

Background:

• Multisystem inflammatory syndrome in children (MIS-C) is a serious condition requiring prompt treatment.
• Interleukin-1 receptor antagonism, specifically with anakinra, is a potential therapeutic option, but its effectiveness in MIS-C is not well-established.
• Understanding treatment variations and their impact on cardiovascular outcomes is crucial for optimizing MIS-C management.

Purpose of the Study:

• To characterize the variation in initial anakinra use for MIS-C across different treatment sites.
• To evaluate the association between early anakinra administration and short-term cardiovascular outcomes in children with MIS-C.
• To compare cardiovascular outcomes in patients receiving anakinra plus standard therapy versus standard therapy alone.

Main Methods:

• Retrospective cohort study of 1,516 MIS-C cases from a US surveillance registry (November 2020 - December 2021).
• Compared patients aged 2-20 years receiving anakinra plus intravenous immunoglobulin (IVIG) and/or glucocorticoids versus IVIG and/or glucocorticoids alone.
• Used inverse probability weighting to balance disease severity and analyzed vasopressor requirement, left ventricular ejection fraction, and C-reactive protein reduction.

Main Results:

• 13% of MIS-C patients received anakinra as initial treatment, with significant site-level variation (0-74%).
• Early anakinra addition was not associated with significant differences in vasopressor requirement (25.6% vs. 20.1%) or impaired left ventricular ejection fraction (33.7% vs. 25.7%).
• No significant difference was observed in C-reactive protein reduction on day 3.

Conclusions:

• Substantial variation exists in the initial use of anakinra for MIS-C in real-world clinical practice.
• Early administration of anakinra in conjunction with standard therapy (IVIG and/or glucocorticoids) did not demonstrate an average short-term improvement in cardiovascular outcomes for children with MIS-C.
• Further research may be needed to identify specific patient subgroups who might benefit from anakinra or to explore alternative treatment strategies.