Comparison of Immunomodulatory Therapies for Cardiovascular Clinical and Inflammatory Markers Outcomes in Mild to Moderately Ill Hospitalized Multisystem Inflammatory Syndrome in Children Patients

Optimal treatment for non-critically ill multisystem inflammatory syndrome in children (MIS-C) remains unclear. We evaluated short-term outcomes in mild to moderately ill hospitalized MIS-C patients fulfilling CDC 2020 and CDC/CTSE 2023 criteria and treated between April 2020 and March 2022 with either intravenous immunoglobulin (IVIG) monotherapy (Group A, n = 17) or IVIG plus corticosteroids (GC) (Group B, n = 22). Cardiovascular clinical parameters, inflammatory markers, and cardiac imaging were compared on days 1, 3, and 5 relative to day 0. The two groups had no significant differences in demographics or illness severity. Group B showed improvement in heart rate (17.8; 95% CI [9.74, 25.8]), mean blood pressure (5.63 [1.61, 9.64]), and body temperature (1.45 [0.94, 1.95]) by day 1, followed by improvement in albumin (0.43 [0.2, 0.84]), CRP (7.56 [3.0, 12.11]), D-dimer (2344 [488.7, 4200.2]), ferritin (1448 [-609.4, 3505.5]), fibrinogen (110 [44.4, 176]), lymphocyte count (1006 [63.5, 1948]), and NT-proBNP (2901 [-349.3, 6153]) by day 3 and left ventricular ejection fraction by day 4-5 (3.84 [0.55, 8.23]). All results were statistically significant (<i>p</i> < 0.05). Group A required more additional therapies, with no difference in hospital stay. Our study concludes that combined IVIG and GC therapy yielded better short-term outcomes than IVIG monotherapy in this patient population, with improvement in cardiovascular clinical parameters preceding changes in inflammatory markers and cardiac imaging.