@article {MerckxE513, author = {Joanna Merckx and Suzette Cooke and Tala El Tal and Ari Bitnun and Shaun K. Morris and E. Ann Yeh and Carmen Yea and Peter Gill and Jesse Papenburg and Marie-Astrid Lefebvre and Rosie Scuccimarri and Rolando Ulloa-Gutierrez and Helena Brenes-Chacon and Adriana Yock-Corrales and Gabriela Ivankovich-Escoto and Alejandra Soriano-Fallas and Marcela Hernandez-de Mezerville and Tammie Dewan and Lea Restivo and Alireza Nateghian and Behzad Haghighi Aski and Ali Manafi and Rachel Dwilow and Jared Bullard and Alison Lopez and Manish Sadarangani and Ashley Roberts and Michelle Barton and Dara Petel and Nicole Le Saux and Jennifer Bowes and Rupeena Purewal and Janell Lautermilch and Sarah Tehseen and Ann Bayliss and Jacqueline K. Wong and Kirk Leifso and Cheryl Foo and Joan Robinson}, editor = {,}, title = {Predictors of severe illness in children with multisystem inflammatory syndrome after SARS-CoV-2 infection: a multicentre cohort study}, volume = {194}, number = {14}, pages = {E513--E523}, year = {2022}, doi = {10.1503/cmaj.210873}, publisher = {CMAJ}, abstract = {Background: SARS-CoV-2 infection can lead to multisystem inflammatory syndrome in children (MIS-C). We sought to investigate risk factors for admission to the intensive care unit (ICU) and explored changes in disease severity over time.Methods: We obtained data from chart reviews of children younger than 18 years with confirmed or probable MIS-C who were admitted to 15 hospitals in Canada, Iran and Costa Rica between Mar. 1, 2020, and Mar. 7, 2021. Using multivariable analyses, we evaluated whether admission date and other characteristics were associated with ICU admission or cardiac involvement.Results: Of 232 children with MIS-C (median age 5.8 yr), 130 (56.0\%) were male and 50 (21.6\%) had comorbidities. Seventy-three (31.5\%) patients were admitted to the ICU but none died. We observed an increased risk of ICU admission among children aged 13{\textendash}17 years (adjusted risk difference 27.7\%, 95\% confidence interval [CI] 8.3\% to 47.2\%), those aged 6{\textendash}12 years (adjusted risk difference 25.2\%, 95\% CI 13.6\% to 36.9\%) or those with initial ferritin levels greater than 500 μg/L (adjusted risk difference 18.4\%, 95\% CI 5.6\% to 31.3\%). Children admitted to hospital after Oct. 31, 2020, had numerically higher rates of ICU admission (adjusted risk difference 12.3\%, 95\% CI -0.3\% to 25.0\%) and significantly higher rates of cardiac involvement (adjusted risk difference 30.9\%, 95\% CI 17.3\% to 44.4\%). At Canadian sites, the risk of ICU admission was significantly higher for children admitted to hospital between December 2020 and March 2021 than those admitted between March and May 2020 (adjusted risk difference 25.3\%, 95\% CI 6.5\% to 44.0\%).Interpretation: We observed that age and higher ferritin levels were associated with more severe MIS-C. We observed greater severity of MIS-C later in the study period. Whether emerging SARS-CoV-2 variants pose different risks of severe MIS-C needs to be determined.}, issn = {0820-3946}, URL = {https://www.cmaj.ca/content/194/14/E513}, eprint = {https://www.cmaj.ca/content/194/14/E513.full.pdf}, journal = {CMAJ} }