Both Corticosteroids and Intravenous Immunoglobulin Protect From Aneurysms in Children With Multisystem Inflammatory...

Multisystem inflammatory syndrome in children (MIS-C) is a post-COVID-19 condition resembling Kawasaki disease, including developing coronary aneurysms. Optimal treatment remains uncertain. This study aims to identify effective therapies for preventing aneurysms in MIS-C and associated risk factors.

This multicenter, ambispective study included hospitalized patients 0-18 years old with MIS-C between March 2020 and June 2023 from cohorts in Poland, Spain, Catalonia and Colombia. Logistic regression analyzed aneurysm risk factors. Treatment efficacy was assessed using Kaplan-Meier and Cox proportional hazards models, with post hoc Tukey's tests for pairwise comparisons.

Among 853 patients, 33 (4%) developed aneurysms, with a median age of 5.86 years (interquartile range, 3.00-11.7). All immunomodulatory treatments reduced aneurysm risk compared with no immunomodulatory treatment: corticosteroids + intravenous immunoglobulin (IVIG) [odds ratio (OR): 0.29; 95% confident interval (CI): 0.13-0.68], corticosteroids alone (OR: 0.27; 95% CI: 0.04-1.02) and IVIG alone (OR: 0.49; 95% CI: 0.18-1.28). Kaplan-Meier analysis showed a significantly lower 7-day aneurysm-free probability without immunomodulatory treatment (92%; 95% CI: 87%-96%, P = 0.011). Hazard ratios indicated a reduction in aneurysm risk with corticosteroids+IVIG [hazard ratio (HR) = 0.29; 95% CI: 0.13-0.65], corticosteroids alone (HR = 0.25; 95% CI: 0.06-1.13) and IVIG alone (HR = 0.49; 95% CI: 0.19-1.25), but no significant differences were observed between these treatments. No additional aneurysm risk factors were identified.

Corticosteroids, IVIG and their combination appear to be protective against aneurysms in children with MIS-C compared with no immunomodulatory treatment. Although the 3 therapies showed no significant differences when compared with each other, only the combination significantly reduced the risk. Corticosteroids may still be a useful option when IVIG is limited.