Objectives Multi-system inflammatory syndrome in children (MIS-C) is a less understood and a rare complication of coronavirus disease-2019 (COVID-19). Given the scarce data regarding this novel disease, we aimed to describe the clinical features and outcomes of our patients with MIS-C and to evaluate the associated factors for the pediatric intensive care unit (PICU) admission. Methods The MIS-C patients under 18 years old diagnosed and treated in three referral centers between July 2020 and March 2021 were included. Data of the patients were retrospectively obtained from their medical records. Results Overall, 76 subjects (24 females) with a mean age of 8.17 ± 4.42 years were enrolled. Twenty-seven (35.5%) patients were admitted to the PICUs. The two most common systemic involvement patterns were cardiac and gastrointestinal. There was only one lethal outcome in a patient with underlying acute lymphoblastic leukemia. Those with higher procalcitonin levels at admission were found to stay longer in the hospital (r = 0.254, p = 0.027). The risk of PICU admission increased with age (aOR: 1.277; 95% CI: 1.089-1.498; p = 0.003) and with decreased initial serum albumin levels (aOR: 0.105; 95% CI: 0.029-0.378; p = 0.001). Conclusion Although there is a wide clinical variability among the patients with MIS-C, we suggest that those with older age and lower initial serum albumin levels merit close monitoring due to their higher risk for PICU admission.

(1) Background: We aimed to describe the clinical features and outcomes of coronavirus disease-2019 (COVID-19) in children and late adolescents with inflammatory rheumatic diseases (IRD) and to measure their severity risks by comparing them with healthy children. (2) Methods: Among children and late adolescents found to be severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) positive via polymerase chain reaction (PCR) test, IRD patients with an at least six-months follow-up duration, and healthy children were included in the study. Data were obtained retrospectively. (3) Results: A total of 658 (339 (51.5%) females) (healthy children: 506, IRD patients: 152) subjects were included in the study. While 570 of 658 (86.6%) experienced COVID-19-related symptoms, only 21 (3.19%) required hospitalization with a median duration of 5 (1–30) days. Fever, dry cough, and fatigue were the most common symptoms. None of evaluated subjects died, and all recovered without any significant sequelae. The presence of any IRD was found to increase the risk of both hospitalization (OR: 5.205; 95% CI: 2.003–13.524) and symptomatic infection (OR: 2.579; 95% CI: 1.068–6.228). Furthermore, increasing age was significantly associated with symptomatic infection (OR: 1.051; 95% CI: 1.009–1.095). (4) Conclusions: Our study emphasizes that pediatric rheumatologists should monitor their patients closely for relatively poor COVID-19 outcomes.