Real-World Study Assesses Variation in Treatment of Multisystem Inflammatory Syndrome in Children

By CardioNerds - March 23, 2023

A study published in Arthritis & Rheumatology assessed the real-world use of treatment with anakinra in children with multisystem inflammatory syndrome (MIS-C).

What Is MIS-C?

MIS-C is a rare condition that can occur in children diagnosed with COVID-19, typically occurring 2 to 6 weeks after SARS-CoV-2 infection. This condition is characterized by inflammation of different internal and external body parts, such as the heart, lungs, kidneys, brain, skin, eyes, or gastrointestinal tract.

Anakinra is an interleukin-1 receptor antagonist that is used for the treatment of rheumatoid arthritis and is under investigation for the treatment of MIS-C. A 2022 study in Frontiers in Pediatrics reported that anakinra was associated with clinical improvements and was safe for use in patients with MIS-C.

Trends in MIS-C Treatment

For this study in Arthritis & Rheumatology, the researchers sought to gather evidence regarding the real-world use and effectiveness of anakinra in patients with MIS-C. They conducted a retrospective cohort study using data from a US surveillance registry. Patients with MIS-C treated with anakinra or another immunomodulator between November 2020 and December 2021 were analyzed.  In total, 1,516 cases from 44 sites were included. Patients were between ages 2 and 20 years.

Results were compared between patients who received intravenous immunoglobulin (IVIG) and glucocorticoids and those received anakinra plus IVIG and/or glucocorticoids on days 0 to 1 of treatment. Day 0 was defined as the first calendar day of immunomodulatory treatment. Inverse probability weighting was used to balance severity. The primary outcomes were vasopressor requirements on day 3 and impairment in left ventricular ejection fraction on days 3 and 4.  The secondary outcome was a 50% reduction in C-reactive protein on day 3.

Of the 1,516 total cases, 193 (13%) received initial treatment with anakinra alone or in combination with another immunomodulatory treatment. The rate of anakinra use as initial therapy varied between 0 and 74% between sites. In fact, site accounted for 59% of residual variance in anakinra use.

Outcomes of Anakinra Treatment

After adjustment and balancing for severity, outcomes were compared between 121 patients who received initial treatment with anakinra plus IVIG and/or glucocorticoids and 389 patients who received IVIG and glucocorticoids. On day 3, there were no significant differences in vasopressor requirements between groups (25.6% vs. 20.1%, respectively; relative risk: 1.27, 95% confidence interval [CI] 0.88–1.84). Ventricular dysfunction rates were also similar between groups (33.7% vs. 25.7%; RR:1.31, 95% CI [0.98–1.75), as were rates of C-reactive protein reduction.

In summary, the authors wrote, “We identified substantial variation in initial anakinra use in a real-world population of children with MIS-C, but no average short-term improvement in cardiovascular outcomes associated with early addition of anakinra to IVIG and/or glucocorticoids compared to IVIG and glucocorticoids alone.”

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