The outcome of severe MIS-C managed at the Italian epicenter of the SARS-CoV-2 epidemic: a follow-up study of 50 consecutive patients

Background: During the SARS-CoV-2 pandemic, we described a peak of a Kawasaki-like disease in children, later renamed multisystem inflammatory syndrome in children (MIS-C). We report the long-term outcomes of MIS-C patients who presented to our center. Methods: We recorded clinical features and outcomes in patients with MIS-C admitted to our institution (February 2020–February 2022), focusing on the long-term outcome of those with a severe course. Results: A total of 50 MIS-C patients (mean age 8.8 ± 4.3 years, 16 females) were admitted. In univariate analysis, the predictors of high-risk disease were older age; high CRP, neutrophils, ferritin, D-dimer, and transaminases; and low white blood cells, lymphocytes, platelets, albumin, and sodium. In multivariate analysis, a more severe course of the disease was associated with sodium ≤133 or ferritin >684. In two months, the symptoms disappeared. No relapses occurred during four years of surveillance. Conclusion: The prognosis of MIS-C is favorable, even in severe cases. MIS-C resolves completely as early as eight weeks from onset and is not associated with other events over four years of observation. In our experience, careful and correct stratification in the initial phases has proven essential in setting up the correct treatment, with full recovery in all cases.