PM2040: Hematological Alterations in Patients of Multisystem Inflammatory Syndrome in Children (MIS-C) a Risk Prediction Analysis Based on a Single Center Experience

Background: Coronavirus disease 2019 (COVID-19) is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). The clinical spectrum of COVID-19 ranges from asymptomatic to severe pneumonia, acute respiratory distress syndrome, respiratory failure, and death. While COVID-19 is primarily considered a respiratory infection, there is increasing evidence of multi-systemic complications of the disease. MIS-C is a rare severe hyperinflammatory condition in children, typically occurring 2 to 6 weeks after acute SARS-CoV-2 infection affecting multiple organ systems. Laboratory abnormalities of MIS-C include elevated serum inflammatory markers, specifically interleukin-6, C-reactive protein (CRP), and ferritin levels suggesting an underlying cytokine storm as part of the pathogenesis of the disease. While increased incidence of thrombotic events has been reported, particularly in age>12yrs, prognostic significance of all hematological parameters in MIS-C disease is not evident, and data is limited. The primary objective of our study was to describe the hematological manifestation in pediatric patients with MIS-C (including neutrophil to lymphocyte ratio (NLR), hemoglobin, platelet count, and markers of coagulation), and secondarily determine prognostic significance of these parameters.

Methods: A retrospective chart analysis was performed for patients diagnosed with MIS-C at our institution from May 2020- March 2021. Patients needing ICU care were used as a surrogate for increased disease severity compared to non-ICU patients on demographics, initial hematological lab values, and length of stay. The significance of differences between the groups was tested by the Mann-Whitney-Wilcoxon test for quantitative variables and by chi-squared test for categorical variables. R software environment was used to perform statistical analysis.

Results: Demographics are noted in table 1. Patients with MIS-C needing a higher level of care had significantly lower platelet count (148 vs. 229, p = 0.001) and higher NLR (9.95 vs. 4.86, p = 0.0008) on initial labs compared to those who did not need intensive care support as illustrated in Fig 2. Patients requiring PICU care also had longer overall hospital stays (7 days vs. 5.5 days, p = 0.0034). Lower hemoglobin, higher ANC, and lower ALC with p < 0.05 were also noted. ANC and ALC are the inputs for NLR (As statistical tests with 13 heme values were included in our analysis, Bonferroni correction was adjusted for a p-value cut off of 0.05/13 = 0.0038).

Conclusion: No dedicated studies on hematologic risk prediction in MIS-C have been published. Data in our patients studied over the first two years of the pandemic demonstrate that lower platelet count and a higher NLR in the early course is a risk predictor for worsening MIS-C necessitating likely ICU support and extended length of stay. In summary, if disruptions in the hematologic milieu are identified early, patients may benefit from early interventions, likely reducing the risk of MIS-C disease and stress on health care systems.