Among pediatric patients hospitalized with COVID-19 or multisystem inflammatory syndrome in children (MIS-C), thrombotic events may be fatal in as many as 28% of cases, according to research published in Blood.

SARS-CoV-2, the virus that causes COVID-19, has been linked with thrombotic coagulopathy since early 2020. Among adults in particular, the risk of venous thromboembolism (VTE) is well-established, with thrombotic events linked with a 23% chance of mortality.

While the risk of mortality with COVID-19 is known be low among pediatric patients, the increased rate of younger patients presenting with fever, cardiovascular shock, Kawasaki disease features, hyperinflammation, and multisystem involvement around the time that the COVID-19 pandemic began led the World Health Organization to define criteria for MIS-C.

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While pediatric patients presenting with MIS-C may test negative for SARS-CoV-2, coagulopathy is a known potential event. For this study, researchers evaluated the prevalence of thrombotic events among children and adults hospitalized for COVID-19 or MIS-C.

Overall, between March and August 2020, the researchers obtained data for 814 patients linked with 853 hospitalization events. Patients were classified into 1 of 3 groups: asymptomatic SARS-CoV-2 infection (289 patients), COVID-19 (426 patients), and MIS-C/MIS-C-like (138 patients). The median age was 10 years in all 3 groups; 27% of patients in both the asymptomatic SARS-CoV-2 and COVID-19 groups had 0 comorbidities, while 51% of patients in the MIS-C group had 0 comorbidities.

A total of 20 thrombotic events, including 1 stroke, were noted during the study period. These events were more common in patients in the MIS-C group (6.5%) than in the COVID-19 (2.1%) or asymptomatic disease (0.7%) groups. Age of at least 12 years, cancer, central venous catheter presence, and MIS-C were all risk factors for thrombotic events on multivariate analysis.

The majority (71%) of thrombotic events noted after hospitalization occurred regardless of thromboprophylaxis.

The overall mortality rate noted in the COVID-19 and MIS-C groups was 2.3% vs 28% among patients with a thrombotic event.

Disclosure: The study author(s) declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures. 

Reference Whitworth H, Sartain SE, Kumar R, et al. Rate of thrombosis in children and adolescents hospitalized with COVID-19 or MIS-C. Blood. 2021;138(2):190-198. doi:10.1182/blood.2020010218