62 - SCREENING MULTISYSTEM INFLAMMATORY SYNDROME IN CHILDREN: ACCURACY OF THE AMERICAN COLLEGE OF RHEUMATOLOGY MULTISYSTEM INFLAMMATORY SYNDROME IN CHILDREN SCREENING ALGORITHM

Background

Multisystem Inflammatory Syndrome in Children (MIS-C), also known as Pediatric Inflammatory Multisystem Syndrome temporally associated with COVID-19 (PIMS), is one of the most serious complications of COVID-19. The clinical features of MIS-C are not unique and are commonly seen in childhood febrile conditions. Thus, there is a need to identify those febrile children with MIS-C to enable early diagnosis and treatment. In response to the health care emergency, a multidisciplinary team from US and Canada developed a preliminary screening pathway for the evaluation of possible MIS-C, included in the American College of Rheumatology (ACR) guidelines for MIS-C (Figure 1).

The objective of this study is to determine if the ACR screening pathway is sensitive and specific to identify patients with MIS-C from other febrile children with suspected but not confirmed diagnosis of MIS-C.

Methods

Retrospective case-controlled study including children assessed at SickKids with suspected or confirmed MIS-C from March 2020 to March 2022. The MIS-C group included all children meeting the most permissive case definition as per international MIS-C and PIMS definitionsand adjudicated by SickKids multi-disciplinary MIS-C working group as having MIS-C, admitted to the hospital and treated for MIS-C; the febrile control group consisted of all patients with a history of three or more days of fever, suspected of MIS-C and qualified for entering the pathway, but who did not fulfill criteria for MIS-C after adjudication by SickKids multi-disciplinary group, and did not receive treatment for MIS-C. ACR MIS-C screening pathway was retrospectively applied to both groups.The diagnosis result obtained using the pathway was compared with the final clinical diagnosis made relying on the WHO definition criteria (criterion standard). From contingency tables, sensitivity and specificity have been calculated along with a 95% confidence interval.

Results

402 children (241 with MIS-C and 161 controls) were included in the study. The median age was 4.18 years (IQR: 1.9 to 9.0) and 237 (60%) were male. The ACR screening pathway had 74% sensitivity (95%CI, 67.3% to 81.4%), and 99% specificity (95%CI, 98.1% to 100%), with positive predictive value of 98% and negative predictive value of 87%. The balanced accuracy was 87%.

Conclusion

The ACR MIS-C screening pathway has a high specificity, sensitivity and accuracy in capturing children with MIS-C at the onset of the disease. To conclude, despite being conducted early in the pandemic with limited data available, the ACR pathway performs well at differentiating children with MIS-C from febrile controls.